wifi mini ipad 2 do not work

my WiFi don work so, i had ios 8.4 for my mini iPad 2, and has a message at my iPad to update to the late ios, but the WiFi did not work, so i download the late iTunes in order to install the software with my lap to my mini iPad 2, and it was ok, no problem at all. But steel with no activation of my WiFi, don't let me to move the button of the WiFi is color white and it has to be green. It was working properly so far, and i left the iPad for a month with any use. (Network error) Watt i missing to do?

Thank you in advance.