Why does my microphone not work?

Dear Friends,

I have a problem with my iPhone 6s Plus. I replaced the lightning connect (incl. microphone and loudspeaker), because it didn’t charge properly. Now after reassembling everything the phone charges just fine - but the bottom microphone doesn’t work anymore. The soundrecoder app doesn’t show any sound. When I try to call someone they can’t hear anything at all, even though I can hear myself through the loudspeaker when I speak really loudly (maybe that sound is recorded through the upper microphone?). Additional Info: When I replaced the lightning connector, the Microphone mount came off as well. I tried to place it back to the case and put the microphone in front.

Is there maybe a cable that I didn’t reconnect properly? The Charging port and the loudspeaker are working fine, so It must be something only connected to the microphone….

Thanks for your help!!