SharePoint suddenly unable to login - starts multiple credential prompts - able to login on premise however.
Suddenly we are unable to login to SharePoint externally to our network.
Internally it works fine.
What could this be?
We had a similar issue at the same time with another server, our ADFS server.
It did the same but wouldn't allow login either on or off network.
I set ADFS to forms-based authentication and it now works but I don't have a root cause.
These must be related to SharePoint, correct??
Is this SharePoint Online or on-prem? What version of AD FS are you on and what are you using for reverse proxy? Does the issue only affect SP, or other workloads (i.e. Outlook, Lync, etc)? Any changes on the AD FS server, claims rules, WIA accepted strings, anything else?