…..nrbfootprintdns.com detected by antivirus while computer is loading

Hi,
I will appreciate any help with following problem my antivirus has detected:
While the Microsoft Outlook was loading my antivirus notified me:

“Cannot guarantee authenticity of the domain to which encrypted connection is established” (please note the rest of the domain name after the dot:
xxxxxxxxxxxxxxxx.nrbfootprintdns.com

I screen captured the problem, and suddenly my free antivirus was turned off by itself, and another version of the antivirus loads and installed.

Thanks again,
Subartara