Accessing AR750S from another router

My AR750S is connected to my main router (Dlink) with a cable and has LAN IP.

When I am connected to my Dlink router (192.168.0.x), what port do I need to open so I can access the Interface of AR750S?

I remember with AR300M, the WAN option needed to be enabled and a specific port was used. Is it the same with AR750S?

Thank you.

SSH is on port 22 and that is typically firewalled on WAN.

Curious, is there a reason you seem to be set up for double NAT, rather than connecting to the LAN bridge?

I dont want to access ssh just the interface of AR750S while I am connected to my main router.

Most times I don’t directly connect to the AR750S (from my phone or pc). It runs a wireguard client and powers my android/tv/roku for streaming services. If I need to change anything or check the status of connections, I first need to connect to AR750S wifi-AP and then access the interface. I am trying to avoid that. This was actually possible with the AR300M and the old FW 2.2x

You can enable ddns and there are several options like http, https and ssh to enable for the wan side.

Thanks. http, https runs on specific ports for AR750S?

For me the AR750S runs perfectly when 2 ports are open.
WireGuard Server 51820
OpenVPN 1194

I found it in documentation here:

4) HTTP Remote Access
This function requires a public network IP.
If your router is behind NAT, you may need to set up port forward in higher level router. It use port 80.

yes. All run on default port

Http 80
Https 443
Ssh 22