Ethernet connection dead

My drive has been inaccessible lately and so I tried the 60-second reset to see if that would reset to factory default. The front status light shows a fast breathing pattern which points to a device failure or ethernet issue. I verified the ether connection is good by plugging the cable into first a printer and then a computer and my router recognized both devices. It won’t recognize the Home Duo. I contacted support and all they could tell me was to make sure ports 443 and 8443 are open with my ISP. My ISP confirms that both ports are open, even though several port checking web sites say they are closed. The ISP says that is because those ports are closed to incoming, unsolicited traffic but get opened when initiated by my side, which is something a web-based checker can’t do. Any ideas on how to fix this?
Thanks!

In the router, find the nat table manually write down the ip address of your device and specify the port range.