Registration Link Changed and Not Working Anymore

I’ve been using s2Member for registrations for a while now without any issues, and then suddenly a few days ago people were unable to set their password after purchase. They used to receive an email like this:

http://tinyurl.com/y9g3ay5j#traildamage.com

And now they receive one like this:

https://traildamage.com/wp-login.php?action=rp&key=pFdX5WWlqwidasivPLq&login=accountname

That second URL just takes them to the Membership page where they can buy a subscription. There is no way to set their password. What should I do? It’s still set to use TinyURL but it isn’t. Thanks for your help!

I’ve troubleshooted this some more and everything is redirecting to my wpForo Forum page, which requires authentication. I’m going to troubleshoot with them as I think that is where the issue lies, now.