Nexus 4, Lollipop 5.1 WiFi Issue

My Nexus 4 device stopped connecting to the Cisco router at work for some reason. I thought it was because the upgrade to lollipop 5.0 (had Kit-Kat before) but I'm not so sure anymore. **I tried:** - Restart the device - Restart the device with safe mode - Restart the router - Change the device WiFi frequency settings - Use static IP at the advance WiFi connection configuration - Forget the router AP and reconnect - Factory reset trough the device settings, recovery mode and complete flashing the Android Lollipop 5.1 factory image. After factory reset I had the connection possible until restarting the device. I checked with/without signing in, nothing new installed, didn't visit the store, just super clean phone - I could connect the network. after restarting the phone I can no longer connect which means it's not an application issue. **Some facts:** - I can connect other Cisco routers at work - Another Nexus 4 after factory reset connects with no trouble **About the device:** - Nexus 4 - Lollipop 5.1 - build number LMY470 - kernel version 3.4.0-perf-gf75bb4f Any suggestion will be welcome, please let me know if I can provide more details.