PS4 Nat 3 R7960P AC3600 router

[SSApple]

Model: R7960P — Nighthawk X6S AC3600 Tri-Band WiFi Router

Firmware: V1.4.1.64_1.3.25

I have a problem switching my PS4 Nat type from 3 to 2. (I can't join VC on discord too, No Route error.)
It was good until I brought Netgear AC1900 wifi range extender, it was working for couple of hours, and suddenly my Nat type switched to 3.

I have tried port forwarding, UPNP, DNZ, factory reset, static IP address for PS4, switching into Router mode, switching back to AP mode, and unplugging extender. 
All of it seem to not work, and now, I switched back to AP mode, and internet connection fails on PS4. 
It works for other devices, such as my MacBook and phone, but not PS4.
Even though I'm connected to the wifi, on the wifi control panel, it says no devices are connected.

You can probably tell that I am desperate to fix this problems, and any help or tip will be appreciated. 

[SSApple · Accepted solution]

Thank you so much. Your response helped me to look through everything again, and I found my issue.

I was only focusing on my netgear router control panel, but actually there was one more router control panel site(I don't know how to describe it, but basically I have two router login sites where I can configure the settings).

So, I reset both of them to the default settings...and it worked. I feel like dumbass spending two days trying to figure out, but now its all good. 
Thanks.

[SSApple]

PS: I factory reset the router, and now I have Nat type 2.
However, I still can't access to multiplayer game, and my discord VC still doesn't work.
Because I didn't change any settings on the router, I am not sure why I still have the problems.

If anyone can help me out, that will be great.

[plemans]

When you say you're switching back to AP mode, it makes me think you have another device before this router. 

That'd cause a different nat type. 

What modem/gateway do you have? 

[SSApple · Accepted solution]

Thank you so much. Your response helped me to look through everything again, and I found my issue.

I was only focusing on my netgear router control panel, but actually there was one more router control panel site(I don't know how to describe it, but basically I have two router login sites where I can configure the settings).

So, I reset both of them to the default settings...and it worked. I feel like dumbass spending two days trying to figure out, but now its all good. 
Thanks.