Is my email account compromised or is it just false flag?

[Swatopluk]

Maybe someone with more IT experience than me can tell me.

I occasionally find 'mail delivery failed' notifications in my email inbox indicating that someone sent out spam under my email address that gets either rejected or was directed at invalid addresses. I have changed my password a few times (after checking the system for malware) but the problem returns. Is this an indication that someone has hacked my email account or is it more likely that someone simply puts a false sender address on his spam without any need to access my email account at all?
My passwords should be beyond guessing or thesaurus attacks (16 characters gibberish) and I do not enter them via physical keyboard but using the onscreen graphical keyboard tool.

[Griffin]

I doubt it is your email has been hacked/compromised.

I've been getting mail delivery failures from this site due to a recent server change. For some reason the new server name had got onto a couple of blocked address lists (ie. block everything from this server). These have generally been connected to humanoid-bots registering as new members.

When a new member registers administrators get an email from the system to tell them. However as the system is itself blocked, they actually come through as failed mail.

This problem came to light when Mero became an undesirable. Then DaveL too.

I have recently (two?three? days ago) managed to get us unblocked, so those particular emails have, I think, stopped.

I suspect there may be a few others of this type too. They may have stopped too. Certainly I have had nothing in the last few days.

Since it is only administrators who should be getting these emails, I have a certain concern that your problem may be different, but of the same nature.

If you could supply the full headers of one of these messages I would be able to work out the problem, if it is us causing havoc. By full header I mean everything that precedes the actual message, but send that too. In your email client/web mail there will be an option to display full headers. 

If this turns out to be nothing to do with us my charge for this service will be waved.