mobile

Hello everyone,
I don't know what happened but the wifi on my nexus 7 2012 (grouper) goes crazy , the wifi icon show it's connected but i don't have acess on network after ~3 minutes on youtube app.
I tried multiple things , set a static IP instead dynamic , set google DDNS 8.8.4.4 and 8.8.8.8, change the wifi channel 1 to 6.
My router is a Sagem Livebox ( french I.S.P. router). I also tried other devices working on android with this router and youtube app worked great. There is no doubt, the problem come from my nexus 7 !

I made a video of my problem if it can be usefull , i really don't understand what happened because i didn't change any network settings maybe it's a hardware problem (hope not)...

P.S: i can't post link because xda saidd i don't have more than 10 post...what a joke i subscribed on xda in 2012 when i got my nexus 7 and today whern i logged in it asked me to link my gmail account and bam now i'm a new user , that's great...