Guest user stuck on loading wheel after accepting an invite?

We've setup our tenant to allow for guest user access to Teams. After inviting a guest user, they have accepted the invitation sent through to their inbox. However, upon opening the link they just see Teams stuck on a loading wheel like below (happens on the web app also).

After trying the same invitation process using a personal email address, I can open into Teams perfectly fine. Does anybody know what might be causing this or whether anything can be done to fix it?

Thanks