This guide will tell you how to solve the Public Session join problem in Grand Theft Auto 5.
The first thing you will need to do is to make sure that your internet connection is working properly in Rockstar Social club. Press the Home button to bring up the Rockstar Social club launcher, it will show your name and online friends.
After that, press the Esc button, go to the Online tab, and navigate to Play GTA Online.
You have to join the Solo Session first. After that, press the Esc button, go to the Online tab, and tap on Find New Session. Now you need to join the Public Session.
If you have purchased the game from Steam, then you have to open the Steam launcher and go to the GTA 5 game. Tap on the Play button and select the Play GTA Online option. It will directly take you to the Public Session.