Can't use 6120 as an access point

I purchased a Netgear 6120 some time back. Until now, I've been using it as a range extender (and have been immensely disappointed and frustrated with the unreliability of the results). As per the manual on https://kb.netgear.com/30080/EX6000-EX6120-initial-installation-as-an-Access-Point , this model can also be connected via ethernet to the router to provide an additional wifi hotspot.

The poor quality of the range extender functionality has led me to try this. I've tried following the instructions above, and I am able to complete steps 1 to 3. However, after plugging the extender into my router via ethernet, connecting to NETGEAR_EXT wireless network on my laptop, and seeing the green DEVICE light on the extender, I am TOTALLY UNABLE to access mywifiext.net. I have tried all of the following:

- using the http://mywifiext.net/ URL

- using the default IP address of 192.168.1.250

- logging into my router, seeing connected devices, and using the IP associated with the only device in the list which is unfamiliar to me (in this case, 192.168.0.40)

NONE OF THESE have worked. All result in the same page (error

192.168.0.40 took too long to respond, ERR_CONNECTION_TIMED_OUT on Chrome).

I have tried connecting to this IP with my laptop on Chrome and IE, as well as my phone, ALL with the same result as above.

In the troubleshooting page regarding being unable to access the above page, https://kb.netgear.com/29746/I-can-t-access-www-mywifiext-net-what-do-I-do , I am told to connect the device (i.e. my laptop) to the extender via ethernet. However, this is in direct contradiction to the access point setup steps posted above, which state that the extender must be plugged directly into the router and that the device must connect over the NETGEAR_EXT wifi.

I HAVE EVEN tried using an ethernet network switch with the extender, router and laptop plugged in, to no avail.

Can anyone advise? This product has totally turned me off of interacting with NETGEAR in a financial capacity again, so I would appreciate some good news for once after buying this piece of rubbish.