mail messed up

[blooz]

Two of my accounts in my mail program (on a mini running OSX.5.6) have that circle with the triangle with the exclamation point in the middle next to them.
Clicking on the icon gives me a message like this:

"The server error encountered was: The server “mail.myaccount” cannot be contacted on port 110."

I have one other account, a Verizon account which also uses port 110 and is okay.

The mail was working earlier today. Isent and received mail, but now nada.

Any clues for the clueless?

[jdc]

restart mail?

then restart mac?

[blooz]

Bingo, jdc.
I'd tried restarting mail, but not the mac. That did the trick. Shoulda thought of it myself, especially as I gave that advice to someone a couple days ago.