##[error][SQ] API GET '/api/server/version' failed, error was: {"code":"UNABLE_TO_VERIFY_LEAF_SIGNATURE"}

[igortos (Igor Tosic)]

I have had the same issue while using sonarqube 9.3.0.51899 running behind the reverse proxy with nginx with SSL.
The solution was to add the full chain (bundle) SSL certificate on nginx and to reload the webserver.