Take All Accounts Online?

All of a sudden, I can't receive my emails. The small triangle with the explanation mark showed up next to the Inbox and the Rogers account. When I click on the Triangle , the Alert message shows up..."There may be a problem with the mail server or network. Verify the settings for account “Rogers” or try again." Or the box for "Take All Accounts Online" shows up, but to no avail. My emails do show up on my Rogers mail account with Yahoo. I'm rather stumped here....any suggestions would be appreciated.