Why my phone Nexus 4 not connect to Wi-Fi networks?

[AC Question]

My Nexus 4, Android version 5.1.1, kernel version 3.4.0-perf-g99f5b2b And the Build number is LMY47V do not connect to Wi-Fi (the wifi enabled the phone see available wifis) and the wifi sign also do not appear on top of the screen only I can save the Wi-Fi network only. When I connect it to a laptop it appears on the laptop screen “No drive”. There is also an exclamation mark with the GSM sign.
I tried the factory reset but the same issue still exists.
All other functions of the phone OK.

 

[B. Diddy]

Welcome to Android Central! Try rebooting your router by unplugging its power for 10 seconds, then plugging back in. See other tips here: http://forums.androidcentral.com/am...roubleshooting-wi-fi-connection-problems.html

When you connect via USB to your laptop, do you see a USB connection notification icon in the phone's status bar? If so, swipe down and tap the notification, then select MTP.

What GSM sign are you talking about? Can you show us a screenshot? http://forums.androidcentral.com/am...ide-how-post-screenshots-android-central.html