Cannot connect to WiFi.

["Juan R. de Silva" <juan.r.d.silva@gmail.com>]

Hi folks,

My ISP replaced my old modem with the new one. I changed my WiFi 
Authentication key and the name of the WiFi network. Then I made Network 
Manager to "forget" my old WiFi. Network Manager finds my new WiFi but I 
cannot connect to it.

When "Authentication Key is required" dialog pops up and the key is 
entered,j Connect button remains grayed out/disabled. Thus there is no 
way to get through but pressing Cancel button. 

I'm running Debian Stretch.

Could somebody help. It's quite urgent now.

Thanks.