Suddenly my phone today could not detect the WiFi SSID for my home router. Strangely all other devices at my home are able to connect.
I was not able to figure out why it is the case and I restarted my Router and Phone. But, it did not help.
I logged into router and checked what is the channel of current wifi connection. It was set to automatic and its value was 12.
I found the issue with my phone plus higher channels.
https://www.reddit.com/r/Nexus5/comments/31ljh5/connect_to_wifi_channel_12_or_13/
I manually set the channel to a lower number (2) and then my phone was able to detect and connect to the Wifi
