[CentOS] help from community

From: Prabhpal S. Mavi <prabhpal at digital-infotech.net>

> Sender address rejected: unverified address: 
> host mail.digital-infotech.net[41.211.25.193] 
> said: 450 4.7.1 Client host rejected: cannot find your hostname, [205.234.223.198]

Is this the issue...?
$ host 41.211.25.193
193.25.211.41.in-addr.arpa has no PTR record

JD