I used the tool here: http://www.mailenable.com/Tools/memaillookup.asp (I'm using Mailenable on a Windows Server machine) for mail.carleadcanada.ca and I get
FAIL, Unable to determine name servers for this domain. This may be because the domain is not registered. Please see www.dnsreport.com for more information on this domain.
What do I do next? And could this have something to do with email bouncebacks I'm receiving with 554 bad reputation messages?