550 recipient rejected - domain has no delivery address DNS MX or A record

[#1]

http://community.plus.net/forum/index.php/topic,100474.16.html
Wasn't going to bump a 2011 thread as its the same fault, but getting it currently with info@yesrecruit.co.uk
ticket 73965675 for headers and full error codes

[#2]

The error is telling you that the domain has no email delivery records in DNS. This doesn't seem to be the case any more though so you should no longer be seeing this error. Perhaps the owner of the domain made some DNS changes recently that took a while to propagate?

>nslookup -type=mx yesrecruit.co.uk 212.159.6.9
Server: cdns01.plus.net
Address: 212.159.6.9
Non-authoritative answer:
yesrecruit.co.uk MX preference = 10, mail exchanger = mx01.1and1.co.uk
yesrecruit.co.uk MX preference = 10, mail exchanger = mx00.1and1.co.uk
mx01.1and1.co.uk internet address = 212.227.17.191
mx00.1and1.co.uk internet address = 212.227.15.134
mx01.1and1.co.uk internet address = 212.227.15.150
mx00.1and1.co.uk internet address = 212.227.17.175