This tutorial is going to teach you how to fix Couldn’t Sign in Google Playstore or “Can’t establish a reliable connection to the server Google play store”. This another problem after flashing any rom. I have two methods and easy to understand I just attached images and videos.
1. Go to settings
2. Set your date and time correctly.
For Videos Watch it!
Go to Settings-Apps
Tap Google Play Store
Tap Force stop then clear data and clear cache
If not work try to factory reset. If still you can download free Playstore Click Here.