Each time I want to insert or change a row or drop a database or a table, an error 404 (page not found) is displayed or, with HTTP or cookie authentication, I'm asked to log in again. What's wrong? ¶

Check your webserver setup if it correctly fills in either PHP_SELF or REQUEST_URI variables.

If you are running phpMyAdmin behind reverse proxy, please set the $cfg['PmaAbsoluteUri'] directive in the phpMyAdmin configuration file to match your setup.