They can log in, but that's about it.
I'm unable to access their profiles from my account, as well.
As an apparent result, I can add them to teams or projects, but they never receive invitations, and cannot access the projects.
Attempting to view their profile always results in this screen:

Meanwhile, if they look at their list of projects, the one they've been added to does not appear.

Unsure how to attempt troubleshooting this. Any help would be appreciated.