@kitz - I had a quick read and the issue seems to be related to mx.avasin.plus.net if I understand correctly
Plus net should have multiple mx records (most likely round robin), so I would think a quick fix from your server would be to hard set 2 mx records for plus net where it is not an issue
Your server should then not do a live dns lookup for mx as it would be pulled from host file, and use a good mx server
Sorry not quite sure if I understand, as I never touch anything to do with the domain name records.
I have just checked in WHM and my MX record is set to kitz.servers.eqx.misp.co.uk which I believe is correct.
afaik, there is nothing wrong with my server (which has nothing to do with Plusnet), but rather its Plusnet's mail servers that are randomly failing to look up domains correctly. I don't use Plusnet mail aside from obviously they send my broadband billing to a PN address.
From what I can gather if their servers are failing to look up the DNS correctly for valid domains and if it can't find the domain it is returning the mail to sender marked the domain doesn't exist... when it fact it does.
In that thread the people notifying Plusnet are companies who have their own domains and mailservers for whom PN are incorrectly rejecting mail. There's a post in there from someone who said they are a large insurance company and their mail isn't getting through to people who are using PN for their email.
The problem is at Plusnet's end and Plusnet customers need to be aware that they may not be getting all their mail if they use PN mail services.
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The only reason I spotted it was because I had sent email to someone who has a PN email address. Plusnet mail servers rejected that mail saying kitz.co.uk does not exist.
Then when I looked further into what was happening I noticed I have a pile of returned emails for members of this forum who use PN mail which were sent from the forum email addresses. These were mostly notifications of PMs or subscribed threads sent out automatically by the forum software. Some of these dated back months. For example there were about a dozen or so notifications to just one of our regular members saying he had PMs to read. He will never have gotten those emails because PN mail servers think there is no such domain as kitz.co.uk and so have rejected and returned them.
It's not just my domain.. as Townman says "
This is not an issue specific to any individual domain. It is quite random. "