verify receivers

Hello there I noticed what option Verify receivers (now is set 550) stopped works. If I try send message via telnet to blabla@mydomain.com proxmox mg answer O.K. Early was work fine. I had switched it to off and back to 450 or 550 – no results. We use proxmox MG as relay and Exchange server...

Hi there, I have enabled (Configuration > Mail Proxy > Options > Verify Receivers > YES (550)) however, I still see logs like this. Why did PMG even accept mail from real user noreply@goodexample.co.uk to non-exisitant user urkelu@kis5.com as kis5.com doesnt even have a MX. Apr 14 11:45:38...