I was unable to log into phpMyAdmin from Firefox. Every time I entered the user name and password, I would be presented with the login screen again. I was able to resolve the problem by removing the coookies for the site on which phpMyAdmin was running from within Firefox 52.0 by the following process:
- Click on the menu button at the top, right-hand corner of the Firefox window - the one that has 3 horizontal bars - and select Options.
- Select Privacy.
- Click on the link under History for "remove individual cookies".
Click on the site on which phpMyAdmin is running to select that site,
then click on Remove Selected. Don't click on Remove All or
you will remove cookies for all sites.
- Click on Close to close the cookies list window.