Has there been an update on this? I’m having this same problem.
I have two sites with Pro. One of them works fine. My other one works fine within the dashboard, but when I go to “Customize Pro in Theme Options” it asks me to log in. When I log in again, It brings up a window asking me where I want to go. My other site does not show this window when I click “Customize Pro in Theme Options.” My other site takes me directly to Theme Options.
My site that it’s not working on https://steffenharris.com, shows this window. When I click on any of the options (Headers, Footers, Theme Options, etc) I get a login window again, but the link I clicked never loads. it just keeps asking me to log in and then select an option. If I wait a few seconds without doing anything, the login prompt opens up.
Wordpress is 5.2.1
Pro is the most recent version
Links in general settings are the same.
No Cache plugin being used