Cannot open phpMyAdmin for the database in Plesk: Access denied for user

Symptoms

• phpMyAdmin shows the following errors on attempt to access the database through Plesk at Domains > example.com > Databases > exampledb > phpMyAdmin:

  CONFIG_TEXT: Connection for exampleuser as defined in your configuration failed

  ---

  CONFIG_TEXT: You probably did not create a configuration file. You might want to use the setup script to create one.
  
  Error
  MySQL said:
  
  #1045 - Access denied for user 'exampleuser'@'localhost' (using password: YES)
  mysqli_real_connect(): (HY000/1045): Access denied for user 'exampleuser'@'localhost' (using password: YES)

• Repair Kit error:

  CONFIG_TEXT: The user johndoe on the subscription example.com is unable to connect to the database server.

Cause

Password for the database user was modified directly in the database server, therefore Plesk has outdated password stored for the phpMyAdmin connections.

Resolution

Password for the database user should be updated in Plesk:

Note: In case any applications are using this database, the new password must match the one specified in the next steps.