I've got a few hosts that have started to show this message everytime they contact bam.

What does it mean?

This happens when the signing key is changed, or was missing during a contact.

We had an outage on the server where BAM! is hosted last week, it may be related.

The only solution known to me is to detach, then re-attach to BAM!. This will have no effect on stats, and in 99% of all cases your host will be recognized by BAM!.

What happens to the WU if we detach and re-attach to BAM.
Will it cancel my current work and start new WUs ??(long wu like CPDN)

Nothing will happen with the attached projects and your work.

That is..... If all goes like it's supposed to go.

So on the affected hosts detach/defect from BAM, then re-attach, then delete the old host or will it reattach as the old host?

Yes.

Do not delete the host in BAM!, then it will reattach as the old one.

Cheers Willy

The process does create a new host in BAM though.

That's exactly the point. It attached as the old host instead of creating a new one.

Let me explain it clearer, following this method does not attach as the old host - a new host is created.

I swear I read "doesn't", but also swear I wasn't drunk!