When a user uses Single Sign-on to log in with Azure they receive the following error:
AADSTS50011: The reply URL specified in the request does not match the reply URLs configured for the application
This error seems self-explanatory and should lead you to verify that the application URLs in Azure for your dbFront application are set up correctly.
One unusual situation can occur if your dbFront application is being projected by CloudFlare. In that situation, your dbFront application could be running as HTTP on your local server while the rest of the world sees HTTPS. For more details see: CloudFlare and dbFront