php problems

When I’m trying to logout, I’m getting these messages:
https://gamingirl.com/wp-login.php?action=logout&_wpnonce=2ae0d5d6d5 (I think you should be able to see it)
The system doesn’t log me out.

I tried to install a few plugins, but most, if not all, didn’t work, talked about the header info already has been sent.

Anyone knows about this?

ps.: downloading a new “pluggable.php” and uploading it to the right place doesn’t help.