Why wifi not connected and not working

@fnkysid there are just to many possibilities to give you a concrete answer. The very first thing you want to do is to go through the Samsung troubleshooting site Follow those directions first.

If none of that is working, then there is a possibility that you are having issues with the WiFi antenna or the WiFi/BT IC on your mainboard. For that follow the troubleshooting flowchart

Measure the voltages according to the flowchart. To identify the location of these components on the circuit board, use the Component Layout and do a search with your PDF reader for the listed number i.e. C3012 and so on.