Over the past two weeks, we've seen a noticeable increase in Microsoft 365 users receiving license validation errors. Examples include Account Validation Error Code 0x0 and several "Something went wrong" messages with tags such as [7ita9] and [5fcl8]. We moved to Microsoft 365 late last year and had very few problems until now. The errors affect users both on and off our network, so I'm wondering whether others are seeing the same pattern and if there's a known service issue or likely cause.
2 Answers
We ran into very similar license validation failures last week. It may be another Microsoft service-side problem, although it’s hard to tell whether the underlying issue was actually fixed or just temporarily disappeared.
We’re still seeing it in our tenant. Interestingly, new users don’t seem to be affected at all; the failures are limited to existing users. That makes it look more like a token, account state, or cached licensing problem than a broad issue with provisioning new accounts.
That’s a useful distinction. Our affected users are also mostly existing accounts, so we’ll investigate cached credentials and license refresh behavior.

That matches what we’re seeing—everything was stable for months, and then these errors started appearing suddenly.