This is usually a bug in the PhpMyAdmin configuration, whenever you receive the following error when accessing PhpMyAdmin either from WHM or cPanel, follow the steps given below for a fix
Manually edit /usr/local/cpanel/3rdparty/etc/phpmyadmin/php.ini file as follow:
1)Login to shell of the server using root login details and open the file “/usr/local/cpanel/3rdparty/etc/phpmyadmin/php.ini” using vi or any other editor.
2) Search for the [Session] variable & underneath it, change the following
session.save_handler = sqlite
session.save_handler = files
session.save_path = /tmp
By default, PhpMyAdmin uses sqlite as as the file handler, but it needs to be changed to files & the location of the session files to be stored needs to be changed to /tmp which is the standard/default place to store temporary files