Why mic is not working of Samsung Galaxy A50 mobile

@biswajitnayak it is possible that this is a bad mic. First you want to try a hard reset of your phone as well. Just make sure that you have backed your pictures and contacts etc. up. You will lose those in a hard reset.

If that did not get any results, you want to check your phone according to the Samsung flowsheet

and the Component Layout

Ultimately, I would replace the charging board since that is where the mic is. At least that way you have a clean, known-well starting point. After that, replace the flex from the charging board to the main board.

Since iFixit does not have any guides yet, use this one to work on your phone.

While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.