Had same problem with htc one m8s since marshmallow update, kept getting 'disabled' message and 'unable to connect' messages when trying to login to home WiFi but no problem on hotspots. Noticed hotspots security mode were WPA2-PSK and home was WPA-PSK/WPA2-PSK. So I logged into my router and changed the security mode at home to WPA2-PSK and hey presto able to log in. Just had to login again with all gadgets though because security mode had changed. I had already rebooted phone and router and contacted htc support but none of these worked till I did above.