iphone 3g when making a call screen goes black help

[foreveraudio]

just restored iphopne 3g to 4.2.1 unlocked it and jb it.
everything works fine but when you place a call the screen goes black

you can take and hear fine and when call ends the screen goes back to home screen just fine

is their a way to fix this issue

thanks

[iYeow]

Sometimes it can be due to improper case that you put on which is blocking the proximity sensor.

[foreveraudio]

no case was on it , and another issues just arose when phone was connected to itunes and backed up, ringer quit working when getting calls just vibrates crazy

[iYeow]

Did you mute the button..

[foreveraudio]

no

[mxkimball]

Just try hard resetting it.

[i.Annie]

If restoring again doesn't fix it, could be the sensor. Be sure to be setting the phone up as new.