It may be that system administrators are allowing usual HTTP/HTTPS traffic but blocked other traffic to that server via their hardware firewalls. This is not unusual in Universities. If HTTP/HTTPS is working, you will have web interface based services working but others such as OpenVPN, etc. will be failing. That diagnostics result just checks if firewalld has properly opened the ports on FreedomBox’s side. It does not check reachability from external sources. I suggest you check with system administrators on whether they are blocking traffic on port 6523. One small check you can do is open SSH tunnel to FreedomBox machine to check if the daemon setup is okay:
ssh -L 6523:localhost:6523 fbxadmin@fbxdomainname
This will open a tunnel from local machine port 6523 to 6523 port on FreedomBox via SSH protocol. Keep that shell alive and then in Gobby, simply connect to
localhost you should be able to edit documents. This is also worst case scenario for all users to do when you can’t get the admins to open ports.