Have you waited a few minutes or longer to try it a second and third time?

Sounds like you caught the server between diaper changes.

Mine works fine ("Keep up the great work" is displayed like normal). HOWEVER, I will say their system has gotten more sensitive about violations these past few months - so be prepared if this continues.

Try another browser (maybe one that doesn't save history) or your phone to see if you can replicate the issue. Sometimes clearing your cache works too. Had a similar issue with the Ad Balance section last year. Ultimately Google support had to look into it and fixed it.

I received my first violation ever (after 15+ years) this past July for a page talking about a defense industry company. It was considered a violation of the "weapons" policy, whose definition is in the eye of the beholder at Adsense it seems. The same page has been running ads for over fifteen years without issue - Society's getting a bit too sensitive about everything, so let's just ban everything.

The reason you see this error message - Adblock. Disable it on Adsense page and reload the page to make it work.

Thanks CommandDork, it was a browser issue. The "violation" turned out to be on an unverified archive type site. Now I've ticked the box allowing AdSense only on verified sites.

That actually worked to your benefit. You needed to authorize only verified sites.

However I agree with CommandDork that Adsense is generating more violation notices lately. We're seeing more in the forums and there seems to be more activity on Google's end concerning ads.

GSC may soon display their Ad Experience Report.

I recently had exactly the same type of message with an archive.org-type site. Never bothered about the authorisation before but as I only now have a few sites running AS I just checked those in.