Problem domain

[DNS Admin]

Hi All,

Can anyone tell me exactly what is wrong with this domain and if it's
breaking any rules?

cpships.com

We're unable to send mail from our MS/exchange system but I can use my
own Linux server to send.  We don't have any other mail issue.

Any MS system I try, can not return any info using nslookup and when I
use dig I get a response but their mx and A records are pointed to
another domain.  I'm thinking they're breaking some rule but not sure
what.

Thanks