If Mirroring toggle is switched on but not able to mirror the screen then, please try out the following steps for resolution:-
1) Kindly ensure that you have the latest version of java installed.
2) Kindly ensure that Java platform SE Binary has access through firewall.
3) Kindly ensure your Wi-Fi router is configured according to the settings mentioned in the link below-
http://teewe.in/wifisettings