Our mail stops going out intermittently

We have had a notes server since notes 3. We are on 6.5.3FP1 - the latest release of Domino. About 3 weeks ago our mail stopped going out intermittently. (About every other day.) No certain time of day. Last night it was at 10 PM. If we reset the domino program it starts up again.

I am not sure where to start. Any ideas?

It seems to have started about the time we put the latest release of domino on - 6.5.3 FP1 release. So I thought I would reverse that release.

Next - we use Norton Corp. It seems to be stopping some emails from going out.

Third we use Spam Sentinel. I have noticed that our # of spam emails has risen from around 1500 a day a year ago to around 100,000 a day now. We have 12 employees. Could we be overwhelmed and that stop emails from going out?

TIA Frank

Subject: Our mail stops going out intermittently.

So, you have one mail server? That much spam would bring one mail server to its knees.

Subject: RE: Our mail stops going out intermittently.

Which fix pack do you have? There was the original fix pack then they replaced that one with a new CF1 named to a diffrent file name only.