If you've installed Divi Ghoster, e.g. as part of the Ultimate Divi Bundle, you may notice that it includes a handy login form customizer feature, which you can access from "Appearance > Customize > Login Customizer".
However, you may find that you get the following error when you try to use and save it:
"Unauthorized to modify setting due to capability"
This error prevents the customizer from saving and so the login form changes are not applied.
To fix this, I suggest first updating to the latest version of Divi Ghoster. I haven't yet confirmed whether this issue has been fixed in the latest version, but hopefully by the time you're reading this it will have been.
If you are unable to update, or updating does not fix the issue, there is a way to manually solve it.
To do so, we need to edit the "includes/functions.php" file within the Divi Ghoster plugin directory (found at /wp-content/plugins/divi-ghoster).
Locate the following line (somewhere around line 1030):
'capability' => '',
and replace it with:
'capability' => 'edit_theme_options',
Save the file, and now the login customizer should work correctly. Note that this change will be overridden if you update Divi Ghoster and may need to be reapplied.