3CX was logging calls with Salesforce and suddenly stopped today.

[shloobrown]

Tested it and got this error:

Server returned a non successful status code - HTTPStatusCode=BadRequest - Reason=Bad Request - Content={"error":"invalid_grant","error_description":"authentication failure"}

 

[leejor]

For something that was working correctly, to suddenly fail, probably means something changed. That could be an update, firmware, patch, hardware, network, or even corruption. A re-boot may "fix" a corruption issue.