Actually, I tried in my normal browser and I see the same white screen with adobe-pass-blahblah, but a few seconds later it redirects to the provider login page.
More than likely they are using an old redirect method, or a javascript one that SF doesn't support
AGuyWithAComputer
You sir are most likely correct as the pop up is a javascript popup and the other sites are NOT using it....they are built into the website itself.
I'm really not sure if allowing popups would work or if we will have to wait on TCM to update. If you happen to have HBOMAX or subscribe to HBO...they have a TCM section with a bunch
of the movies....I didn't make a comparison, but HBOMAX has over 700 TCM movies currently.