Hi , i am not able to talk on speaker. On speakers I am not audible to other side

Hi , I bought Iphone 6 just 2 days back and and from the starting i am not able to talk on speaker. whenever i keep my phone on speaker the person on other side cannot hear me. Please suggest if i need to change any setting or its an issue.

I can talk normally or on earphones without any issue. Problem occurs when i keep my phone on speaker .