I got this from a client:
“apparently when he goes to reply to my email he get’s a message that I am an unrecognized user. I am confused and it doesn’t make sense.”
I have seen this before…I think the full error is “unrecognized user in virtual host file” or similar. I have inquired, of course.
I found nothing when searching for this string on the Vmin site, so I likely have it slightly wrong.