DHCP Reservations: "Failure! Please check your inputs."

Absolutely irrelevant to the question.

There was no mention of a WAN static IP; the question is about the absolutely useless DHCP reservation process (don't get me started on the broken port forwarding... what is port forwarding without an internal port???????????).

I encountered the same thing today. Yesterday I set up DHCP reservations without issue. Today, I try to set ONE and I always get "check your inputs." The Inputs are an IP address and a comment. Comment is not needed, but since I'm grasping at straws, I tried it anyway. Unsurprisingly, it didn't work. I won't even mention that in the App every single device reservation I created still shows the OLD IP address on a subnet that does not exist. If I check the device it has been assigned the correct IP address.

This is no way to manage internet traffic. I'm going to return this useless plastic box and use my own modem, it's worth the extra money I have to pay if I go over the bandwidth cap (you know, the artificial scarcity that Comcast pretends exists in order to charge you more for using the service you.... already pay for).

I almost didn't move into this apartment because the only ISP available was Comcast. Now I'm absolutely regretting the decision. I'll never move into an area where Comcast is the only ISP again. This is clownshoes nonsense.