Hi everyone. I was just doing some research on Viber, the VoIP app, and I noticed there's a setting that overrides the Android OS settings regarding switching off WiFi. If you have Viber, and you're WiFi isn't turning off, then have a look in the Viber settings for 'Wifi Sleep Policy'. - 'Always connected'. Which I think is the default setting.
Turn that off.. and that MIGHT help some of your problems.
My issue is simple. Should WiFi be left on, or automatically switched off when sleeping?? I'm still not sure, but I'm going to carry on reading.