OK, nevermind - I figured it out. Sorry to bother you!
Looks like I was mistakenly trying to add more than five email addresses to one contact whereas I was intending to add more than five different contacts. The latter you can do, but not the former.
Can you point me to some help with the chess.com mail feature. I have an address and it is set up and working fine. I can send and receive mail, have it forwarded, etc. My question, however, is about the address book feature. I tried entering several addresses and then got a message about having a limit of 5 addresses in my address book. Is it indeed correct that I can only store five contacts in the address book?