Lower Mic not working on voice memo and calls after repair

After replacing my earspeaker (with flex/power cable) the lower microphone stopped working (microphone not working during calls or voice memo).

When recording a voice memo and playing it later I can hear some clicking noises.

People who are calling me say they here noises like a fax or something.

I've tried to replace the dock connector with microphone but this didn't help.

Tried to clean all the grounds/connectors with isopropanol, didn't help.

With a headphone/microfoon connected memo and voice calls is working.

Any help/tips are welcome!

Thank you!