Actiontec WCB6200Q Extender cannot connect to 5G

[mephisto1]

• The SSID on the gateway router is "abc" for both 2.4 and 5Ghz.
• The SSID on the extender is "abcx" for both 2.4 and 5Ghz.
• The password is the same for all.

A few days ago I changed the password to a set of diceware words. However, the extender was not using the new password, even though the new password was showing up on the interface for both bands. (Windows 10 WiFi status showed that the extender was in fact still using the old password.)

I had to go back to factory defaults and set up the extender from scratch to get it to use the new password. The 2.4 works, but I STILL can't log into the extender's 5ghz, with EITHER password. Windows 10 WiFi status says "attempting to authenticate" and then dies. Again, the interface alleges that the extender is using the new password for 5g, but I can't log on.

Help!

[mephisto1 · Accepted solution]

Solved my own problem. It seems the extender cannot handle multiple-word passwords very well, especially on the 5g side. I went back to a letter/symbol/number combo, no spaces, and now everything is working. Annoying.