EX6120 Connection Issues

I have a EX6120 that is having connection issues. Because it is a long distance from the router I would like to disable the 5G and also update the firmware. I cannot access the network manager settings. I have reboot and factory reset the extender many times. I have tried myw1fiext.net(changed because the website didn't like a live link), mywifiext.local, 192.168.1.250, and my router IP address through a PC and two iOS devices but nothing has got me to the manager page. It does make it more challenging that my router is not a Netgear router, so I can't log in through that either. I tried Netgear support as well, with free access about to run out in a few days. Over chat they helped me until the factory reset component. I can figure how to press the factory reset button on my own. On a different case number by phone call they helped with trying the different browser addresses. He said I was unable to access the Setup webpages because they were having server issues. Not quite sure why that would be an issue if it was a local to me address. Does anyone have any bright ideas?