Strange intermittent email problem

Factual Questions
1

We have four computers at my office, a small business. Recently we noticed that they can’t send emails to one another, but they can all still send and receive emails to the outside world. This followed, although perhaps not immediately, a switch of where our email was hosted (and the ownership of the host servers). All are set up with Outlook Express and use POP and SMTP servers.

I cannot find anyplace in Outlook Express set up where it might say that “Don’t send email for these other few servers the same way; use something internal instead”.

Also, in what is possibly a red herring, a secondary server internal to our office (the email stuff is all hosted externally AFAICT) just up and died. I was never quite sure what this thing was doing, so asked someone, and was told it was just a backup for when we switched to the new server (sometime ago) and so wasn’t really doing anything.

Any ideas of where to look to fix this?

Thanks,

Shibb

2

What exactly do you mean by ‘can’t send emails’.
Do they get rejected with an error message? If so, tell us what it says.

3

No rejection message. They just don’t get received by the other party.

4

Hmmm that is weird.
But it looks like the problem is on the receiving end anyway, rather than not being able to send.

So something like an incorrectly configured spam filter might be the problem.

An obvious solution doesn’t jump out at me, but here is what I’d do to try and figure things out:

Download and install another email client. Anything really, just to see if you can receive the emails on that one. If yes, then it is a configuration problem with the receiving machine’s Outlook.

If that still doesn’t work, then contact you provider’s help desk. They can track the email and see if it’s being delivered OK. (Maybe they are trying to spam-filter for you and it isn’t set up right?)