Screens application on Mac not working

I have been using an application on my Macs at work and home called Screens, it lets me do simple screen sharing. It has been working fine for well over a year and then one day it stopped. Turns out after a call to Comcast, they "fixed" my static IP issue, but it busted my Screens app from working.

After a number of contacts with the Screens software developer he said to set up port forwarding manually. I followed his directions and have indeed set that up correctly, I think. But the app still does not work. I can connect to my computer at home (on a Charter/Spectrum router there) but can not connect to my Macs at work, the one I am on now. So this leads me to think its some setting in the Comcast router stopping it.

The general consensus is Comcast support will not help me in the advance settings of the router because "I am not suppose to be in there".

I am looking for somebody who knows this stuff backwards so I can get this up and running again. Help!