We are having similar problems migrating from Fabric to Twitter.
After following the link sent via email from the connection tool and selecting the app to connect, we are redirected to a confirmation page with the error “Sorry, we are unable to process your request at this time.” And the app is not actually migrated.
The account we are trying to connect to is @randomosdinf123 (It’s a valid account but not public-facing so the name is intentionally a bit obscure.)
Thanks for any help you can provide!
Peter