WiFi connectivity flopped - Why?

This Wifi is an exclusive one it is not meant for public and I use it at home

This has nothing to do with access to your WiFi AP by others.

Think of it this way you are in a room and you are talking to a friend in the room you have not issues talking.

Now you turn on the TV and the radio, the oven timer is going off as well as the smoke detector from the burnt meal, your baby is crying and the door bell is ringing it would be hard to have the same dialog with all of that noise.

That's the issue here! It's not people listening in to your communication, it's the air waves that are so jammed up with others also trying to get to their WiFi AP which is sitting on the same bands yours is.

Install the app I pointed you to and lets see what it tells us.

Thank you I have understood the concept and I have installed the app I will post you with the information.