Scenario: An issue was recently reported by Byjus pertaining to SMS templates and Send SMS option for one particular user's login only.
1. While going to APPS--> SMS templates, the user was getting this error page-
Reason: The agency user API credentials were disabled. Dev team enabled them from the backend and it started working then.
2. While going to a specific lead's details page--> Send SMS option--> below error showed up:
Resolution: Access keys were not generated for the Agency User, so after taking login credentials from the user and generating it, it worked fine.
So one needs to know that whenever there are APPS/connector related issues, first thing to check is if the API Keys have been generated for that specific user's login.
Note: API keys generation is User specific and not Account specific.