Hi There
Would you be able to have this user try a few things for me? First, if you could get this user to Clear their browser Cache and Cookies, or try another browser completely?
I have seen in the past particular extensions/toolbars/adware programs can prevent the page from being displayed correctly in Classic.
If you find this doesnt work, let me know and Ill have a support rep reach out to assist further.
Thanks!
Regards,
Ben