I have the same problem, I can't login to mysql, but when I change my password manually and auth_type to config then I get this error:
Cannot connect: invalid settings.
and I can't see login page anymore.
How to fix this? this is so annoying, changing password should be much easier!!!
[EDIT by Altrea]
splitted from original thread because potentially unrelated - one thread per unique user and issue rule
[INFO] How to not fail getting help here (Section "Board and thread structure")