I have several developers that are not able to accept their App Store Connect invitations. I have even tried to invite myself using an alternate email and all users get stuck at App Store Connect website with an infinite loading screen.
Spinning Circle when developers attempt to accept App Store Connect invite
[Error] Failed to load resource: the server responded with a status of 401 () (termsOfService, line 0) [Warning] [blocked] The page at https://appstoreconnect.apple.com/activation_ds?key=df24ec4fcd5e976c7486770c328829be&providerName=MOBILE%20APPS&subType=COMPANY requested insecure content from http://www.apple.com/filenotfound. This content was blocked and must be served over HTTPS.
[Error] Failed to load resource: Redirect was not allowed (createService.min.js, line 0) [Error] Cross-origin script load denied by Cross-Origin Resource Sharing policy.