554 this message has already been here
It all started out as an innocent tidy up on my domain names:
as I wanted all of those sites to point to this one seeing as I've not got anything else to put there. So I logged into mydomain.com and changed all the details which worked. But while I was there I decided that it was time to sort out the mail forwarding as well, not that there was anything wrong with it though. But I wanted to make it nicer ;-)
I set up 0gravity.co.uk to send all mail to rentboy.co.za and forgot that I did that and then sent rentboy.co.za to send all mail to 0gravity.co.uk ! So needless to say it screwed up quite bad and I've lost mail since sometime on Sunday night when I made the change. The only reason I noticed it was because I tried to mail myself from work and got a failure report with that 554 error message.
At least this error message was actually descriptive for once! I've now changed the setup so that each domain will forward it's mail direct to my POP3 account. I initially wanted rentboy.co.za and wasabi.za.net to forward their mail to 0gravity.co.uk which in turn would send it to my POP3 account - but as Andy pointed out that was a bad idea as a failure on 0gravity.co.uk would result in problems with the email on the other domains.
We're still using our POP3 account from freeserve (evil evil people!) as I've been too lazy to try and convert over to blueyonder. But I'll need to get that done soon as I'm not sure how long the freeserve account will be active for.