Error while loading message content - XFinity

I see where there was a series of posts about this problem on 9/19/16
"Error while loading message content. Folder Draft (Inbox, etc.) has been closed on mail server
Probably your request took too long."
I can't open any email whether in the INBOX or DRAFT, etc.
I was in the process of editing a draft and I can't complete.
Can someone advise what to do?
I rebooted the laptop severasl times.