php - after cpanel upgraded to mariadb i can't connect to database -

i have dynamic website on domain made using codeigniter framework.

i don't know how cpanel upgraded mysql mariadb. when open website says:

unable connect database server using provided settings

i checked credentials ten time - correct. checked db connection in using core php testing, give error:

access denied user 'root'@'localhost' (using password: no)

my user not root , password not empty. it's not taking credentials string correctly.

before up-gradation working correctly.

please me should do.

check mysql/mysqli/pdo connection credentials, have somewhere specified root username , host localhost, , mariadb, fork of mysql, see here... wikipedia article