Hiya - my mail.boxes started filling up this morning and weren’t routing mail to my ISP ( relay). I hadn’t changed anything on the server, no changed config, nada. After scouring the forums here, I tried all the things that people recomended - DNSServer=, FQDN in the server document, disabling the DNSblacklist…nowt.Finally, after hours and many disgruntled users, I found a fix. The mail.box was either corrupt or there was a corrupt mail doc.
I stopped the smtp and router services, and loaded fixup, compact -c and updall on mail.box and mail1.box. Restarted the smtp and router services and most of the mail shifted upon restart of router. There were a few dead ones left, but at least things were flowing again.
Hope this helps someone
cheers, T