Ex6120 ac 1200 wif fi password incorrect but not

[Keith2321]

Have connected the extender to the router, and devices shoe the existing 2 networks in 2.5 and 5 GHz plus the _ext extension, but when you try to join the extended network, using the existing WiFi password, it comes back incorrect password.  Router is supplies by EE

[plemans]

Have you tried logging into the extender with a hardwired connection? Does it work this route? If not, the hardwired connection will allow you to log into the extender and change the wifi password. hardwire in and to to mywifiext.net

What firmware is on the extender?

Model number of the router helps as well.

https://www.netgear.com/support/product/EX6120.aspx