mysqli_sql_exception: Access denied for user

Symptoms

When logged into cPanel and trying to access phpMyAdmin, you are presented with an error:

mysqli_sql_exception: Access denied for user 'user'@'localhost' (using password: YES)

Description

This often occurs due to a stale browser session or a desynchronized cPanel user password. 

Workaround

• Clear your browser cache and try again:
  How to Clear your Browser's Cache
• Use an incognito window in your browser to force a clean session:
  How to view your website in Private Browsing mode
• Reset your cPanel password to synchronize it with phpMyAdmin:
  How to reset a cPanel User’s Password