If you can provide some details, I'd be happy to help investigate this with you.
Any details at all could be useful, but to give you some suggestions:
- what browsers are they using? Does this happen with every browser?
- what OS are they using? Does this happen with every OS?
- if you log in with their username/password from where you created the class, do you see the problem? (In other words, is the symptom unique to their user accounts, or to the system they're trying to log in from?)
- do they also see the same problem if they use "Try it now" to access the site instead of using a username/password?
Kind regards
D