If you log in to cPanel and see errors such as:
The system failed to create the file “/home/$USER/.cpanel/datastore/.tmp.e0953.MOUNTS_CACHE__proc_mounts” with permissions “0600” (as EUID: ###, EGID: ### ###) because of the following error: Permission denied
Note: $USER represents the username, and ### represents the UID/GID of the user.
The error indicates that the user's .cpanel directory may have bad ownership or the files within it.
You can check the user's file list with this command:
ls -al /home/$USER/
Be sure to check directly in the .cpanel directory as well:
ls -al /home/$USER/.cpanel
You will need to review the files' ownership and ensure that the user properly owns them. Changing the files' ownership can be done with the "chown" command in SSH or the Terminal in WHM.
Please note that there is no single command to perform the fix, as each scenario may be different. As such, you will want to work with a systems administrator to ensure that the ownership and permissions are correct across the account.