Sender address rejected: "invalid" TLD in MX record

[indcraig]

Reporting-MTA: dns;bigfish.com
Received-From-MTA: dns;mail191-db8-R.bigfish.com
Arrival-Date: Tue, 19 Mar 2013 10:30:03 +0000

Final-Recipient: rfc822;name@companyname.co.uk  (changed email to protect email)
Action: failed
Status: 5.7.1
Diagnostic-Code: smtp;554 5.7.1 <name@companyname.co.uk>: Sender address rejected: "invalid" TLD in MX record
Remote-MTA: dns;mdfmta006.tch.inty.net

http://forum.demon.net/topic/undeliverable-re

After reading through the above and a couple of other recent forum/posts regarding this issue I thought this would be the most apt place to find a solution.

I have only been made aware of this pre-existing problem by staff today. They informed me that since 01/02/13 they have had their email changed to 365 and this this upgrade they have started recieving MAILER-DAEMON errors from clients whom they never had any problems with before.

I've included the log of one of these failures, hopefully someone can assist. I can provide any information which may assist.

regards,

indCraig

[Plumly]

Hi indCraig,

You probably got an MX record on your domain called,

Record MX

Priority 50

Value msxxxxxxx.msv1.invalid

If you remove this entry from your DNS Management page, this NDR will no longer happen,

Thanks
Plumly

[indcraig]

Hi plumly, I'll check this solution next time I'm in work. Thanks for the post.

[Plumly]

no Worries Craig,

did you manage to test this,

Thanks

Plumly

[indcraig]

not yet, I'm the IT person at quite a few small businesses and this particular one I've not been back into yet. Promise to re-visit the thread once I've been in.

[indcraig]

it seems like the problem was on BT's side. I was in this workplace last week and the problem had been resolved by BT tech staff. Staff mentioned something about the daemon failure message being switched to webmaster..... I was only in for 2 hours to fix problematic computer.