Screen goes black when dialing from my lumia 730

[WPCentral Question]

Hi, I'm using lumia 730 DS since from jan'2015...just two days ago i had updated windows 10 mobile preview 10586.29..just from this whenever i make a call my mobiles screen goes black even if i wave my hand just above the sensor it didnt work. (with 8.1 it didint happen?)

what should i do now? how to rectify this issue? advice/guide me.

thanks in advance.

ganesh.