EX2700 unable to connect to home router (but can connect to phone hotspot)

[jeffreyabr]

We have a Netgear EX2700 which has been hooked up to my father's home office for about a year now. It was important that we have this model because it has the ethernet jack in the bottom to connect to his work phone. 

It has worked just fine until recently. I attempted to log in and see the connection settings. It appeared to be connected to our home router properly. However no devices could get internet. 

So I tried running through the Smart Setup again. It says it has a connection but devices ar e unable to get internet.

So I updated the firmware to the 1.0.1.58 img that I got from this website. That went fine.

Then I tried a factory reset. 

It looks like it sets up fine, but after restarting with the newly applied router connection settings, I cannot access Mywifiext any more and must go to 192.168.1.250.

Once I get here after a setup, it tells me that 

The Extender was not able to connect to your existing network.
Please re-enter the password and try again.
Selected Network: [OURSSID]
Security Protocol: WPA-PSK [TKIP] + WPA2-PSK [AES]
Password (Network Key)
[OURPASSWORD]
If you entered the correct passphrase, and the Extender did not connect to your existing wireless network, you might need to move the Extender closer to your router or to a position with a better line of sight. Check the Extender LEDs to isolate the problem. The LEDs are explained in the installation guide and user manual for your product.
If you have Access Control List (ACL) enabled in your router. Please make sure you have added this device MAC address into your router’s Access Control List (ACL).
The Extender MAC addresses are ---------.Your wireless adapter MAC address is ------------.Click 'Cancel' to select a different network.

I wasn't sure whether this was an issue with the extender, so I did another factory reset where I configured it to connect to my Android phone's hotspot. This time, it managed to connect.

Then I tried to log into the dashboard on the extender again to reconfigure the wifi connection to our home router, but I could not access mywifiext or 192.168.1.250 (even though I could pull up pages on Reddit)

So now I'm not sure what the issue is. I did another factory reset, but I cannot get the extender to connect to our home router which hasn't changed or been moved in the last year. I'm not sure what the difference in the connection could be.

Is there anything more I can do from here?

[plemans]

What router are you connecting it to? 

When you're setting it up, before its initially connected, its default ip address is the 192.168.1.250.

I'd factory reset it again and hardwire in a pc/laptop to the extender for setup. Make sure to disable the wifi on the pc/laptop that you use for setup so it doesn't default back to that connection. Then use the installation assistant to set it up. Don't hit the wps button during setup. 

[jeffreyabr]

The router is an Optimum Online provided DIR-868L. I set this network extender up with it in April of 2020, and nothing in the home network has changed (software or hardware).

I was able to access the EX2700 through 192.168.1.250, with the exceptions I laid out above. 

I can try the hardwired factory reset when I get home later tonight. Never used the WPS button, but I'll keep that in mind.