phpmyadmin error : Connection for controluser as defined in your configuration failed
this error occur when phpmyadmin is unable to login to its phpmyadmin database , so this error caused by mostly uninstalling/updating/reinstalling phpmyadmin or mysql .
to fix this we have just to update phpmyadmin config-db.php file with valid mysql account
login to server and edit config-db.php file which can be found normally in
can be edited with vim / nano or other editors , personally i like nano
apt-get install nano # for debian / ubuntu yum install nano # for CentOS
then to edit config-db.php
cd /etc/phpmyadmin/ nano config-db.php
then update these two lines with mysql account , which can be root account or you can create new user account in phpmyadmin users tab
save it by pressing Ctrl + X , nano will ask to save file press Y
and finally reload phpmyadmin and error will be disappeared .