Once the SMS is generated by ShowingTime, it is sent to the mobile phone carrier for the next step in the delivery process. Sometimes this error message could mean a setting needs to be reviewed between the owner of the number and the carrier, or it could mean the number is no longer accepting messages. In other cases, it can mean the carrier is having a temporary outage or is blocking notifications from some numbers.

We can recommend a few things:

• Verify the number is correct in ShowingTime
• Verify that the number is set to receive text messages 
• Check with your carrier for any known outages or issues

Please note: ShowingTime cannot troubleshoot carrier issues.