This is very peculiar. Once a password has been established with plain alphabetics or whatever, there is no requirement anywhere that there must be other characters in it.
But you type this correct password and the connect button stays grayed out.
I am wondering if there are two levels of password involved, one in your phone, and another to get thru the modem. And perhaps you have not set up the one in your phone that it is asking for.
I am not familiar with the specifics so this is just a guess; something to make the actual behavior make sense.
Are you talking about accessing thru a WiFi connection? So you turn on the phone, it scans for WiFi hotspots, finds one, and asks for the password as part of the connection process? Or is it some other network access process?
EDIT: I just looked at the thread title
and so yes, we are talking about WiFi access. So there is no other password that should be required.
I too am stumped. Hope you find an answer, and soon