We have (in the past 3 months) come across 3 domains we have had problems sending email to. Users try, get the "message delayed" bounce-back, then 2 days later get the dreaded "undeliverable" message.
We manually resolve the IP of their mail server using MXToolbox, then create a send connector on our Exchange server. With that, emails leave the building with no issue whatsoever. This points to a DNS issue, I think. There is some DNS server out there between our Exchange and theirs, that can't resolve properly. The DNS servers between MXToolbox and their Exchange obviously has no issue.
I have never had to do that up until recently, but it is averaging 1 per month since May. It isn't that big of a deal to me to create 1 send connector per month. It takes 30 seconds. I see this as a FIX. My boss sees it as a WORKAROUND. He suggests we need to open a paid support ticket with Microsoft to resolve it, but I happen to think it is a problem with something far out of our control.
So my question; Is a send connector a FIX or is it a WORKAROUND? I know in the grand scheme of things it is a workaround, but when the problem is out of your control, it's description gravitates closer towards the FIX designation, because it is all you can do on your end.
Any tips as to where the error might be (given the really vague details) would be welcomed, but that is not really what I am searching for.