I'm having some odd issues with one of my clients not being able to send emails to the domain kohinoorfoods.co.uk via my server.

From Exim's logs:

2012-12-31 12:01:09 1Tpe3E-0001wT-Fy kohinoorfoods.co.uk [50.57.203.17]
Connection refused
2012-12-31 12:01:09 1Tpe3E-0001wT-Fy == xxx@kohinoorfoods.co.uk
R=dnslookup T=remote_smtp defer (111): Connection refused
2012-12-31 12:01:09 1Tpe3E-0001wT-Fy == yyy@kohinoorfoods.co.uk
R=dnslookup T=remote_smtp defer (111): Connection refused
2012-12-31 12:01:09 1Tpe3E-0001wT-Fy == zzz@kohinoorfoods.co.uk
R=dnslookup T=remote_smtp defer (111): Connection refused

Oddly they can send mail to them from their Blackberry, but to me their DNS looks wrong - no MX records for a start (ip is of their web server).

I checked the following two websites to verify that it wasn't just me:

http://centralops.net/co/DomainDossier.aspx?addr=kohinoorfoods.co.ukanddom_dns=trueandsvc_scan=true

http://dnscheck.iis.se/?time=1356957861&id=2916138&view=advanced&test=standard

However their IT support advise: "Looking at their logs it appears that when they are doing the DNS lookup to find the MX records for your domain its unable to find any records, this to me indicates a problem with their DNS server, the site they have used to check http://centralops.net doesn’t seem to find any MX records for your domain, but if I google MX Lookup and run the same test from at least the top 5 MX Lookup sites I can successfully see that the MX records are a.mx.apm-internet.net and b.mx.apm-internet.net

As there is on one person who seems to be having this problem I would suggest therefore that the problem is actually with the DNS servers that they are using to route mail out, if multiple places were reporting the same problem then it may be a problem with whoever hosts your domain."

Can anyone else verify that this isn't just a problem with my server?

Thanks

Gavin