Emails not coming in through any program

I'm also not sure what category to put this in, so if there's a better suited one, please tell me.

Yesterday any e-mails coming through an e-mail program no longer come through.

I'm a primary thunderbird user, and when I saw my phone notifying me e-mails are coming in, and my thunderbird would respond with, "No new messages," I checked the situation with Mail and that program did the same thing. Loaded everything up the same e-mail and then "No new messages."

I did try sending an e-mail out through thunderbird and it went out just fine.

I'm not really for sure what the issue is, and I'd love it fixed as soon as possible, I'm just not sure where to start.

Any help is greatly appreciated.