SMS message sent via Pinpoint returning PERMANENT_FAILURE with Invalid Message Body error

Question

My application allows users to send out SMS messages. We use Pinpoint to send out the messages. Most messages are getting delivered. But occasionally we see messages with delivery status as "PERMANENT_FAILURE", status code of 400 and delivery status message as "Invalid Message Body". The message body has been logged and can be viewed and nothing stands out as invalid. Are there any characters that cannot be in a message? How can we identify root cause of this error?

Andrii S · Answer

Hello.

The error message "Invalid Message Body" suggests that there's something in the SMS body that's not acceptable or incompatible with the SMS protocol or Pinpoint's handling.
SMS messages are typically encoded in the GSM 03.38 character set. Some characters outside this set might cause issues. Even if you're using Unicode (UCS-2) encoding for sending SMS messages to support a broader range of characters, there's a limit to which characters are supported. Lastly, you can also build a test suite that sends out a variety of SMS messages containing different character sets, lengths, and formats. This way, you can proactively identify any potential issues and make necessary adjustments before sending messages to real users.

Regards, Andrii

SMS message sent via Pinpoint returning PERMANENT_FAILURE with Invalid Message Body error

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