the caller can't hear me

[AC Question]

my phone is sony xperia ST27i when i receive a call the caller can't hear me and when I a making a call the receiver can't hear me what might be the problem and how can i solve it?

 

[Dave_M104]

I had a similar problem on an Xperia, turned out to be a headphone jack issue. Phone didn't recognise when headphones were removed.
Hope this helps.