I get Attempted to use login credentials, but they were invalid even though the credentials are 100% true.
I guess they are too complex for this tool.
My password is like: J-GHs[Rx.6[Ggdfaqe8Ay
I used it like this: perl mysqltuner.pl --user myuser pass='J-GHs[Rx.6[Ggdfaqe8Ay'