Why Is My Outlook Classic App Not Opening After License Changes?
Asked by
TechGuru87
I work for a managed service provider (MSP) and today we've been dealing with multiple complaints about the Outlook desktop (Classic) app not starting up. When users attempt to log in, they encounter the Error CAA2000B alongside the server message AADSTS500014, indicating that the subscription is lapsed or that the application has been disabled by the Administrator. I confirmed that we haven't disabled anything, and I double-checked the settings to find that the service is still enabled. All affected accounts have an active license for Exchange Online (Plan 1). Interestingly, after I switched one user's license to Business Basic, everything worked fine again. I was able to revert back to Exchange Online Plan 1 and still had no issues. Has anyone else experienced this bizarre licensing problem or have clarity on what might be causing it?
Answers
Check the Enterprise Applications section in Entra for the service principal ID. It's likely been disabled. For me, it was the Microsoft Information Protection API that caused the issue. Enabling it fixed the problem. Not sure why it got disabled, still waiting on Microsoft for an explanation.
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We're experiencing the same issue today. Microsoft keeps insisting we're not licensed correctly, which isn’t true!
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Thanks for sharing this. After a lot of troubleshooting, I’ll add a couple of other error codes we encountered, like the sign-in error code 500014. Hopefully, this helps others find a solution!
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TroubleSolver99: This solution worked for all our clients too. Big thanks for the heads up!
UserFixIt: Exact same issue happened for us overnight—suddenly affecting many users. Your help saved us after hours of trying to troubleshoot!