Accessing network from outside?

I very recently upgraded to xfinity xfi and have a new TECHNICOLOR CGM4331COM gatemay modem.  I've alway's used a NOIp dns domain to access my network from the outside.  Primarily via FTP.  I run my own domain and on my main domain controller I run the noip agent that updates my outside IP adress.  Since going to this new router I've rebuilt my doamin controller and I've not been able to connect remotely via my external IP address or the noip domain name.  I have FTP port 21 forwarded to the internal server running the ftp server like i've always done.  Inernally the ftp site works fine.  I did disable advanced protection on the router hoping that was simply blocking it but that didnt' seem to make a difference.  I'm at a loss as to what could be going on and how to get this working again.  Any ideas or help would be greately appreciated.