Unable to login after upgrade to v7.0 (Raspberry Pi 3B)

Hi All,

yesterday I’ve upgraded to Grafana v7.0, everything went on without errors, I rebooted but now I’m unable to log in…it says “invalid username or password” but I’m 100% sure about credentials.
It’s strange because I logged in just before upgrading so I clicked on “forgot your password?”, typed the mail but I didn’t receive any mail so far.
Is there another way to reset the password?
Grafana is installed on a Raspberry Pi 3B.
Thank you, regards.