Problem with the speaker? PHONE CALL: I hear the person who calls me but he does not hear me. Problem with the speaker?

I would like to know if this is a software problem or a physical problem of the speaker.
While having the call pushing the button “loudspeaker” then the other one can hear me.
This F2 Fairphone is already a replacement of the first one i got and had to send back beecause of other problems!
How shall i ever recommend Fairphone to my business partners? too many trouble.

A post was merged into an existing topic: Microphone not working anymore

Duplicate of topic linked above; posts moved accordingly.