Configure GL-MT300N-V2 over WAN

I would like to configure my MT300 using my office computer…which is connected to my home LAN with a cable. I have FIOS and use multiple routers connected through the coax/TV cables and the MT300 is connected to one of those other routers and appears active with an address assignment. When I try to open the administrative panel using that address, the MT300 won’t connect.

Do I have to use a specific port on the MT300 to connect eg:

Is the only way to configure the MT300 through a wired LAN (not WAN) or wireless connection?

Stumbled on my answer…it’s in more settings/advanced settings/networking/interfaces…I had to set the WAN port to accept input

Yes, you need to set the WAN port to accept input.