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SMS Error Codes

While sending messages, CallHub system sends the message to the telecom carrier and the carrier notifies CallHub if the messages were successfully sent, delivered or failed. Telecom carriers use error codes to identify the reason for the message failure, which can be viewed under the “Error Code” column in the SMS Report. Error codes are described in the table below:





Unreachable Destination Handset

The recipient's number is unreachable. The number could be out of service or may not accept messages.

Message blocked

If a message you sent is not delivered to the end device it means message failed as the destination number is blocked from receiving this message.


Unknown Destination Handset

The destination number is unknown or no longer in service.

Landline or
unreachable carrier

The destination number is unable to receive this message. Potential reasons could include trying to reach a landline or, in the case of shortcodes, an unreachable carrier.


Carrier Violation

The number is blocked and the messages are filtered and/or marked as “Spam” for violating carrier regulations.


Unknown Error

The telecom carrier has returned a generic error message. Telecom carriers have no information about this error, it could be that mobile is switched off or not in-network.

Invalid destination number
The destination number you entered is either not entered correctly or not SMS-enabled.
Failed to dispatch Message
An error occurred while sending the message to carriers. This is an internal failure, and messages with this error code will be retried at a later time.
Unknown error
Delivering your message failed for reasons that are unknown to us and to our carriers.

The above error codes will help you to identify and understand the cause of the message failures for your campaign. If you encounter an error code that is not included in the list mentioned above, let us know in the comments or send us an email to

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  1. Mahesh Nayak

  2. Posted