Sony Xperia Z5 Microphone Flex Replacement

Hello! After the microphone replacement the primary microphone still isn`t working! Only the secondary microphone is functional! I have tested that using the xperia diagnostic app and the service menu! the other party cannot hear me when calling, the microphone works fine when recording a video! I have already done a factory reset, it did not help! what else could be broken which blocks the primary microphone signal?!?!