Can't Connect to Internet

[7Bridges]

I've been using Gargoyle on a few routers for several years and have been using it on a Archer C7 v2 (first on version 1.9.1 then 1.10.0) for over a year but suddenly I can not access the internet.
I have Dish Network Satellite Internet with their ViaSat modem. With no changes to settings suddenly I get this message with Mozilla Firefox via wired connection "You must log in to this network before you can access the Internet" If I click on the message it takes me to an Excede login page.
Internet Explorer just says "This page can't be displayed"
Via wireless on an iPhone, Safari just takes me straight to the Excede login page. I called Dish and they said it was a Router issue.
If a plug the PC directly into the modem bypassing the router everything works fine and when I revert the router back to the Factory TP-Link firmware everything works fine.
If I re-install Gargoyle the same issue occurs.
Any help anyone can give me would be greatly appreciated.

[Lantis]

Is your modem a bridge or is it doing NAT?
I’d say they’ve made changes that make it incompatible.

[7Bridges]

I assume it is doing NAT. The attachment shows the ipconfig command results when the PC is plugged directly into the modem. My apologies, I'm sure it is obvious that I am no expert at this.
I didn't make any changes to the default Gargoyle setup. I just added Static IP Addresses and Quotas (Overview and Connection-Basic Screenshots are also attached)

[Lantis]

Please host them externally and I’ll take a look.
I don’t have any good ideas at this stage however.

[7Bridges]

How would I go about hosting the screenshots externally?

[ispyisail]

greenshot with imgur

[7Bridges]

The screenshots can be viewed at:
https://imgur.com/a/FAC2ePN
Let me know if there is any more info you need. Thanks

[ispyisail]

Your provider is looking for the correct MAC address?

[7Bridges]

That fixed it. Many thanks.

[ispyisail]

What was the problem? (for other people searching this thread)