Part of the Furniture
I use a long passphrase and use spaces in my passwords.
While not a crisis, if Asus changes which characters are allowed that would be unfortunate.
Their popup help says 'letters and numbers' which suggests no symbols or punctuation.
I use the first letter of each word in an easy-to-remember passphrase, plus some key numbers inserted at key places. For example:
"The grass is always greener on the other side."
Becomes WPA Pre-Shared Key: tg2021iag2021otos