Vipe P1 marsallow update won't download on wifi but works fine on data

[Mohamed Farid2]

I have a lenovo vipe p1 and I received the marshmallow update but it won't download using wifi , when I switch to mobile data it works fine .

While on wifi it won't find an update when check for updates , tried starting the download using data then switched to wifi it stops downloading until I switch back to data .

Any idea on how workaround this !?