Postfix Started Rejecting Incoming Emails
Very strange problem here. All of the sudden I get a call from a customer saying they can't get any emails and they're bouncing back. However, they are able to send out just fine.
I do some testing and all emails sent to all domains are bouncing back with the following:
(some user)@(some domain).com (550 5.1.1 <(some user)@(some domain).com>: Recipient address rejected: User unknown in local recipient table)
I then checked through the posts on here with the same problem, verified the main.cf and virtualusertable and everything looked fine. I restarted ispconfig, restarted postfix, even restarted mysql to no avail. I checked the ispconfig log and found no errors.
Then, out of the blue, they all start going through again. So at this time they are all working but I need to find out why they stopped working and why they all the sudden started up again. I'm afraid this problem may come back and there's no apparent reason why.