Error: Form security failed. / Fehler: Sicherheitschecks fehlgeschlagen

since this morning i got the problem - that after typing in my username/password i get the notice:

Error : Form security failed. Please reload the form and check that your cookies are enabled. If you use a proxy server, you must configure Matomo to accept the proxy header that forwards the Host header. Also, check that your Referrer header is sent correctly.

or in german:

Fehler : Sicherheitschecks fehlgeschlagen. Bitte laden Sie das Formular erneut und prüfen Sie, ob Ihr Browser Cookies zulässt. Wenn Sie einen Proxy Server verwenden, müssen Sie Matomo so einrichten, dass es Proxy Header akzeptiert.

although the server ist not behind a reverse proxy and the browser allowed to get cookies.

anyone an idea what the problem could be?

thanx tom

Just reload the page and login will be possible again. Got this message today on one of my Matomo instances aswell.

hi fabian - does not work on my side ;( (cache deleted / hard reload)

That is strange, can you provide the PHP error_log?

hi fabian, will post it tommorow (just started php error_log) - thanx for your support :wink: tom

hi fabian,
in the meantime we found the problem - PHP error_log was the right place to search in - Error query: SQLSTATE[HY000]: General error: 1114 - so a simple database is full.
the matomo error just lead me in the wrong direction :wink:
thanx for your help.

Glad you have been able to work it out.