How to change the SMS default error message?

When a user sends an SMS message to the platform and an unhandled error occurs, the following message is sent back to the user: "Sorry, but your message could not be processed. The error has been logged. Please try again."

This message can be customized using Service Center. To do this, login to Service Center with manager permissions. Select the "Phones" option and scroll to the end of the page. There is an "Error processing the inbound message:" field, and this is the one you have to change to customize this error message.