What to do when i can't here them and they can't here me on my lumia 550

[Aaditya Kakroo]

I can not here others and they can not here me (when I call others or they call me)

 

[Chintan Gohel]

I can not here others and they can not here me (when I call others or they call me)

While on the call, try increasing call volume by pressing the volume up key
Or put on speaker