Problems saving new network names and passwords (CAX30 AX2700 Modem Router)

...many weeks later, I've finally gotten around to re-addressing this problem. The Nighthawk app now seems to work for me to manage the router settings (it was basically useless during setup, not functioning as expected). I used it to change the network password to the 5GHz band, which included a special character. Same as before, I received an "incorrect password" error when trying to connect my devices to that band, despite entering it in correctly multiple times. I tried including a different special character - same thing. I then created a password with only alphanumeric characters and that did the trick. I ultimately tried incorporating 3 different special characters, one at a time, into the password (!, #, and @) and all caused a problem. This is disappointing as I'd like to make my password as complex as possible. Thanks again for your time.

TL;DR - Apparently using special characters in my network passwords does not work; I was finally able to successfully change the passwords using only alphanumeric charaters.