Have them read my blog and see if anything there helps. Find out what their OS and browser is, and what they're using to get online with ie a PC, MAC, phone, etc.) Have them contact the staff directly via Help & Support at the bottom of the page if they can't fix the problem and it doesn't "fix itself" (it may be a temporary glitch depending on what OS, browser and/or device they're using to get online with)
http://blog.chess.com/NimzoRoy/diagnosing-and-fixing-internet-problems
We have developed a Monday Night "chess club" meeting for DHLC members. We all join the chat room and set up games, analysis boards, etc.
This past Monday evening from 6 PM to 7 PM EST, we had (at least) two members who, when they clicked "chat room," got an empty room. They could not see the half dozen or so members who were in chat. We sent them URL's, links and other navigation tips, but they never were able (to my knowledge) to see the others in the chat room.
Dr_Cris_Angel is one username involved.
Any advice?