Ipad with skype working and facetime dont

Hi,

I have a 3d gen ipad updated with the ios8 and when i try to connect via facetime i get the connection but the video it is not working and i have the white over black message with poor connection problems. In the same moment i can use skype and the video works very well, the speedtest also shows full speed. I have a connection of 10 mbps and i am behind an airport extreme AP.

Can anyone help me??

thanks