SUCCESS!!
So I was having the same frustrating SPINNING WHEEL issue while using Logic Pro as many others... but I made one change that seems to have fixed the problem!
I just turned off my internet connection (WiFi) then tried opening the plugin in Logic, but this time instead of it causing the constant spinning wheel, it prompted me for my account login info (...because of no internet connection).
But this time where I had previously been connecting over my home Wi-Fi... I instead connected to my iPhone via PERSONAL HOTSPOT... typed in my password and it loaded right up!
And after that first successful attempt I now seem to be able to use my home Wi-Fi without any issues and everything seems to be working as it should!
DANG....FINALLY!!!