You do not control a MySQL user named "$username"

Symptoms

When changing a cPanel account's username, you encounter an error similar to the following.

You do not control a MySQL user named “$username”.

Description

The error occurs when the cPanel user's MySQL user is missing. Resetting the cPanel user's password from WHM will recreate the missing database user.

Workaround

1. Log into WHM as the ‘root’ user.
2. Navigate to "Home / Account Functions / Password Modification."
3. Select the account on which to change the password.
4. Enter the new password in the "New Password" and "Confirm Password" text boxes.
5. Click the "Change Password" button.

Additional resources

Password Modification