Yesterday I installed the Twitch Extension on my channel and managed to get it to load and configure. Now, whenever I go into MyExtensions and try and bring up the configuration it gets stuck, just spinning the wheel forever. I have uninstalled and reinstalled the extension, logged in and out of my twitch account, and tried on another browser. If I log in to my other Twitch account, which also has a DnDBeyond account for that login, it will configure fine. I have also tried various combinations of being logged in to DnDBeyond while configuring on twitch, or logged out, with matching and mismatched logins, etc. But from mt Variant Roles twitch account, it simply will not load the configuration menu anymore.

I was having the same issue. And i don't know if this will fix it for you, but i wasn't aware that the twitch account needed to be part of the campaign to be able to load the configuration.

I joined our campaign with the twitch account we streamed on, made a random character, then in the configuration of the extension just deselected it.

Hope this helps!