Troubleshooting Tip: FortiAuthenticator is unable to send SMS message with response error code 105

To troubleshoot SMS integration issues in FortiAuthenticator, follow these steps:

1. Verify that the SMS gateway is properly configured and test the connection.
2. Check the FortiAuthenticator logs for any error messages related to SMS integration. For example, as below : 
                                              
3. Ensure that the SMS gateway provider's certificate is installed on the FortiAuthenticator.
4. Verify that the sender ID is correctly configured and approved by the SMS gateway provider.
5. If using a numeric sender ID, note that some SMS gateways may not accept numeric sender IDs and may require an alphanumeric sender ID.
6. To customize the sender ID, contact the Fortinet sales team or partner to raise a New Feature Request (NFR).
7. To customize the default SMS template used by FortiAuthenticator, go to System -> Administration -> Replacement Messages.

Note: 

The default SMS template used by FortiAuthenticator is: 

Your%20authentication%20token%20code%20is%20123456.

If issues persist, verify the template and sender ID configuration with the SMS gateway provider.

To run packet capture, follow the commands below:
Technical Tip: How to run a Packet Capture with FortiAuthenticator
Follow the link below to debug FortiAuthenticator services:
Troubleshooting Tip: How to debug FortiAuthenticator Services