Echo when on speakerphone

Hello, when i use the speakerphone during a phone call or a video call(Whatsapp, Facebook etc) the other person is hearing echo of his voice or a lot of noise.

I can hear him perfect and he hears me ok. The problem is when the otherone is speaking.

I have tried eveything i found on this site but nothing helps. (noise reduction, clear cache and other system settings)