SMS and MMS Error Codes: Examples and Solutions

Meaning: 4302 identifies the sending number; 4303 identifies the recipient number.

Example: A copied contact number is missing a digit.

What to do: Confirm the destination with the customer and review the selected business line. Correct the number before trying again; changing the message will not fix an invalid number.

Meaning: Sending is forbidden (4403) or the sending number’s account association/configuration is invalid (4407).

Example: Calls work on a newly added line, but texts fail.

What to do: Check that you selected the intended business number. Ask Zonitel to verify SMS/MMS enablement and account configuration. Voice service alone does not confirm messaging is ready.

Meaning: The destination was rejected as invalid or unavailable for that messaging service.

Example: A customer provides a landline that cannot receive texts.

What to do: Confirm the number and whether it receives business SMS/MMS. A recipient-side restriction can also be involved. If the customer wants the messages, they can ask their mobile provider to review their restrictions; do not assume a typo or spam block.

Meaning: 4406 indicates an unassigned destination; 4721 identifies a deactivated destination.

Example: An older contact record still contains a discontinued mobile number.

What to do: Verify a current number and consent before updating the contact. Stop attempts to the old number. Do not assume a replacement number belongs to the same customer.

Meaning: 4001: service not permitted. 4493: sender unauthorized for the account.

Example: An integration selects a line that is not authorized for its account.

What to do: Confirm the selected business line and give Zonitel the exact error. Ask us to check service access and sender authorization. Do not reuse another account’s credentials or keep submitting the same request.

Meaning: The recipient is not allowed for this messaging request.

Example: A multi-recipient request includes a number type that the route does not accept.

What to do: Check the recipient number, messaging capability and selected sending method. Ask Zonitel to identify the rejected destination. Do not assume every contact in a list is invalid because one request failed.

Meaning: 4405: sender unallocated or inactive in messaging records. 4740: source address rejected by the destination network.

Example: A recently activated line can make calls, but the messaging route does not accept it yet.

What to do: Check the business line selection and ask Zonitel to review number activation, messaging records and destination support. Include whether the issue affects one destination or several. Do not edit customer numbers to fix a sender error.

Meaning: The destination’s account association or receiving configuration could not be resolved.

Example: The number appears valid, but its receiving messaging configuration cannot be identified.

What to do: Confirm the destination and share the complete record with Zonitel for routing and configuration review. This does not mean you must add the customer to your own account or change their portal permissions.

Meaning: 4433: toll-free messaging not enabled for the account. 4434: messaging to the toll-free recipient is forbidden.

Example: The selected route cannot send a text to a toll-free customer-service number.

What to do: Tell Zonitel whether the toll-free number is the sender or recipient. Ask us to review the relevant permissions and messaging capability. Keep this separate from 4795, which concerns verification of the sending toll-free number.

Meaning: The business messaging route rejected an emergency-number destination.

Example: An emergency number was entered as the recipient of a test message.

What to do: Stop the attempt and check the recipient field. Never send test messages to emergency numbers. This business-texting error must not be used as evidence that an emergency request reached a dispatcher.

Meaning: 4476: sender unregistered. 4773: campaign inactive for the destination. 4774: number provisioning problem.

Example: The campaign was approved, but a newly added sending number is not fully activated.

What to do: Give Zonitel the sending number and exact error. Ask us to verify the campaign status, number assignment and completed activation. If registration was rejected, use the campaign rejection guide below. Wait for confirmation before retesting.

Meaning: The toll-free sending number lacks the required messaging verification.

Example: A toll-free line receives calls, but its texting verification is still pending.

What to do: Ask Zonitel to check verification for that specific number and provide any missing business or consent evidence. A local-number 10DLC registration does not verify a toll-free number. Resume only after confirmation; verification does not guarantee delivery.

Meaning: An opt-out blocks further messages from this sender.

Example: A customer replied STOP, then an appointment reminder was attempted.

What to do: Stop sending and check Conversations → Group Messages → Opted-Out (Unsubscribed). Preserve the opt-out. Do not delete the contact or change the sending number to bypass it; follow the opt-out guide if the customer independently asks to subscribe again.

Meaning: The message was filtered as suspected spam.

Example: A promotional text fails even though the business has an approved campaign.

What to do: Review consent evidence, the registered purpose, actual text, links and sending pattern. Identify the business clearly. Send Zonitel a representative failed example if the issue persists. Do not rotate numbers, disguise words or repeatedly resend to evade filtering.

Meaning: The shortened URL in the message was rejected.

Example: A reminder contains a public shortened link that hides the destination.

What to do: Use a clear HTTPS link on your business’s own domain and verify the destination. Keep it consistent with the registered program. This improves clarity, but no URL guarantees delivery; ask Zonitel to investigate a continuing block.

Meaning: 4481 identifies a sending-number block; 4482 identifies a receiving-number block. 4772 can involve either side.

Example: A campaign is active, but its number still encounters a network block.

What to do: Pause affected sends and ask Zonitel to identify the blocked number and reason. Include the exact code and consent context. A block is not automatically an unsubscribe record or proof of a particular violation; do not rotate numbers to bypass it.

Meaning: The messaging service could not download the media.

Example: An integration references an image link that expired or requires a login.

What to do: For a portal upload, reattach the original file and review the preview. For an integration, have its owner check media access and link validity. Keep private files protected; do not publish sensitive documents merely to make a link accessible.

Meaning: The MMS exceeds an applicable media-size limit.

Example: Several photos fit individually, but their combined size is too large.

What to do: Reduce image dimensions or video length, compress the files, or remove unnecessary attachments. Follow the limits shown for the composer and number type. Test the smaller file once; an upload being accepted does not guarantee the destination accepts it.

Meaning: The media type could not be accepted or interpreted.

Example: A specialized image format fails on the customer’s device.

What to do: Export a real copy in a broadly supported format such as JPEG or PNG, then check the composer’s accepted types. Renaming the extension does not convert a file. Compatibility can vary by device, destination and sending-number type.

Meaning: The destination rejected the message length.

Example: A full page of instructions is pasted into one SMS.

What to do: Keep the essential information in a shorter text and place the remaining details on an appropriate business webpage. Avoid breaking it into a rapid series of repeated texts. Send one revised test after confirming consent and the supported limits.

Meaning: 4409: invalid destination messaging profile, often involving MMS support. 4700: service type rejected.

Example: A recipient can receive a plain SMS but cannot receive the attached picture as MMS.

What to do: Confirm which message type the recipient can receive. If appropriate and consent remains valid, use one plain-text message with the essential information. Ask Zonitel to investigate recurring capability errors; successful voice calls do not prove MMS support.

Meaning: The message cannot be processed with its current character encoding.

Example: An integration produces corrupted text after copying content from another system.

What to do: Preserve the failed example, then prepare a short clean-text version for one authorized test. If an integration generated it, have its maintainer check encoding. This code does not mean all accents or emoji are prohibited.

Meaning: The message passed an initial check but was invalid when being sent; the destination number may be involved.

Example: A request is initially accepted, then fails when the destination is processed.

What to do: Recheck the complete recipient number and exact error description. Give Zonitel the message record if they look correct. Initial acceptance is not delivery, and changing the wording alone may not fix this result.

Meaning: The receiving network rejected the message structure or a data value.

Example: An automated template produces an empty message when a required value is missing.

What to do: Review the final rendered text, attachment and recipient fields, not just the saved template. For an integration, ask its maintainer to inspect the request. Fix the identified field before one test; the code does not identify a universal character limit.

Meaning: The request or destination network rejected its number of recipients.

Example: An integration puts too many addresses into one group conversation request.

What to do: Ask Zonitel to confirm the limit for that exact sending method. A shared group conversation and a Group Messages broadcast list are different workflows; do not apply one participant limit to every list. Review recipient-level results before retrying anyone.

Meaning: The destination service or subscriber is unavailable.

Example: The customer’s phone is off or temporarily unreachable.

What to do: Confirm the number and check the latest delivery result before retrying. If receipt is still needed and a temporary problem has cleared, make one controlled retry. Ask Zonitel to investigate repeated failures; the code does not prove a specific phone setting is responsible.

Meaning: The destination network reports no usable messaging route.

Example: A roaming customer cannot receive the message through the available route.

What to do: Share the affected destination, sending number and timestamp with Zonitel. Confirm the destination is supported. Do not change text or create a new campaign based only on this error; routing needs investigation.

Meaning: A rejection was reported, but its precise cause was not supplied.

Example: An appointment reminder fails and the record contains only a general rejection.

What to do: Check recipient capability, consent and content, then provide the complete record to Zonitel. Do not label it a confirmed spam block. A recipient restriction or handset issue is possible, but the code alone does not identify the cause.

Meaning: Sending exceeded an applicable allowance or was throttled.

Example: A large batch hits the campaign’s throughput limit.

What to do: Pause additional sends and ask Zonitel to confirm the relevant allowance and when to resume. Space future sending appropriately. Do not assume one universal limit or bypass it with extra numbers; some throttling can also relate to messaging quality.

Meaning: Processing failed, a service was busy, or a destination queue could not accept the message.

Example: Several otherwise valid sends fail during a temporary interruption.

What to do: Check the latest status and ask Zonitel about a broader issue. For a confirmed failed send, allow time for recovery before one authorized retry. Stop and escalate if it repeats; do not keep resending to a queue or an uncertain result.

Meaning: 4360: the send deadline passed. 4794: the destination carrier expired the message.

Example: A time-sensitive reminder cannot be processed before its expiration.

What to do: Check whether the information is still useful. If a new message is appropriate, update its timing and content and verify consent before sending once. Never resend an expired appointment reminder automatically.

Meaning: No delivery receipt arrived within the reporting window; the outcome is unknown.

Example: The portal has no final confirmation, but the customer says they received the text.

What to do: Record the customer’s confirmation and review the latest report. Do not assume delivery or failure from the timeout alone. Avoid duplicate sends; ask Zonitel to investigate if confirmation is important. A receipt is not proof that someone read the message.

Meaning: A downstream error was returned without a recognized cause.

Example: The report shows an unknown error instead of a specific explanation.

What to do: Send Zonitel the exact status, code and description with the message details. Do not treat this as the same result as 9902 or choose a fix from the code alone. Avoid repeated retries while the result is being clarified.

Meaning: The rejection was reported at the handset.

Example: Delivery fails at one customer’s device while other recipients receive the same notice.

What to do: Ask the customer, through an appropriate existing contact method, whether they want the message and can receive this type of text. Share the result with Zonitel. The code alone does not identify a device setting, and it does not justify repeated sends.

Meaning: 4401: routing rejected. 4420: destination network missing from the route configuration. 4421: destination permission or provisioning missing.

Example: A test accidentally uses the same number as both sender and recipient, which can produce 4401.

What to do: First compare the two numbers and verify the intended destination. If correct, send Zonitel the code and timestamp for routing review. Do not replace these codes with 4730 in your report; the exact result helps locate the problem.

Meaning: 5101: a processing application was shutting down. 5111: the associated connection had already closed.

Example: A send fails during a service restart or connection interruption.

What to do: Check the latest message status and whether there is an ongoing service incident. Ask Zonitel before retesting repeated failures. After recovery, use at most one authorized retry of a confirmed failed message; refreshing your browser alone does not prove recovery.

Meaning: 5106: routing attempts could not complete. 5201: the service expired the message after unsuccessful attempts.

Example: The service tries to process a reminder but never completes the route.

What to do: Check whether the reminder is still relevant and ask Zonitel to review the attempts. Do not start a new retry loop or automatically resend stale information. Coordinate any new test after the underlying route or service issue is resolved.

Meaning: Message storage failed during processing.

Example: A send is rejected because the processing service cannot save it.

What to do: Give Zonitel the exact timestamp and message reference. This is not an instruction to clear your phone’s storage or delete conversation history. Confirm the final status and service recovery before a controlled retry.

Meaning: The service could not assemble the complete message before its waiting period ended.

Example: A longer SMS arrives at the processing service with a missing segment.

What to do: Preserve the original message and error for Zonitel. Check integration processing if applicable. After review, a concise replacement may be appropriate; do not send the missing fragment by itself or create repeated bursts of messages.

Meaning: The send failed because an available destination could not be obtained.

Example: The record has a valid-looking number but the service reports no destination for the send.

What to do: Confirm the intended recipient and give Zonitel the full error for service and routing review. Do not assume this proves the number has been disconnected. Retest only after the relevant issue is corrected.

Meaning: 5610: a submission or cancellation operation failed. 5620: destination application error. 5650: sending to the destination failed.

Example: Several sends fail while the receiving network is experiencing a processing issue.

What to do: Tell Zonitel which operation was attempted and provide its latest status. A failed cancellation does not confirm cancellation. For a confirmed failed send, coordinate one retry after recovery; stop if the problem repeats.

Meaning: The network did not provide the expected processing acknowledgement.

Example: The service reports an acknowledgement error while handling a send.

What to do: Ask Zonitel to review the message’s final result before trying again. This is a processing acknowledgement, not a customer reply or read receipt. Do not assume the message was unread, and keep 5630 separate from the delivery-receipt timeout code 9902.

Meaning: The messaging service reported an unknown internal error.

Example: The report contains 5999 without a more specific diagnosis.

What to do: Send Zonitel the complete description, status and message reference. Avoid choosing a fix from the word “unknown” alone. Keep 5999 distinct from 9999, which represents an unclassified response from the destination network.

Meaning: This sender or service cannot message the destination country.

Example: An international recipient is outside the available MMS coverage.

What to do: Confirm the country and the SMS/MMS service involved, then ask Zonitel whether that destination is supported and enabled. Voice calling coverage is separate. Do not change the country code to force a domestic route.

Meaning: 4451: invalid user identifier. 4452: invalid application identifier or account/sender association.

Example: An integration retains an application reference from a different configuration.

What to do: Have the integration maintainer and Zonitel verify the identifiers against the intended account and line. Share references privately without passwords, tokens or API keys. These service identifiers are not necessarily the name of a portal user you can edit.

Meaning: The requested messaging channel is unsupported by the destination device.

Example: A connected messaging service attempts a channel the customer’s device cannot use.

What to do: Confirm the actual channel in the failed record and ask Zonitel which alternatives are available for your setup. This entry is relevant only when the exact code appears; it does not imply that every messaging channel is included in your account.

Meaning: 4431: short-code service not enabled. 4790: destination short-code restriction. 4791: short-code campaign not allowed. 4792: short code not provisioned on the destination network. 4793: short code expired.

Example: An existing short-code program encounters a restriction on one mobile network.

What to do: Use this case only for a record involving a short code. Ask Zonitel to review the exact restriction or activation state. Do not apply these codes to a local-number 10DLC campaign or assume short-code service is available in your account.