How to fix error code 403 on Google Play Store (Nothing else worked)

Every device has a secret menu designed as a fail-safe in case if the operating system misbehaves and fails to perform. In this menu, there is a cache partition stored. This partition, if it gets corrupt can be a reason for errors, including this one. In this case, you need to wipe this cache partition, after which it will be renewed with clean versions of the files that were corrupt.

To enter the recovery mode and wipe the cache partition, follow the steps below: 

1. Turn off the device
   
   
2. Press and hold the Volume (+) up and the Power (Sleep/Wake) buttons. Once your device turns on, let go of the buttons.
   * If you use a Samsung device, press the Power (Sleep/Wake), Volume (+) up and Home button.
   
   
3. Press the Volume up or Volume down key to navigate through the options. Highlight the Wipe cache partition then press the Power (Sleep/Wake) key to make the selection.
   
   

   

If the other solutions didn't work, consider resetting your device to its factory settings, which will remove the corrupt system files from your device and resolve many issues along the way. Those corrupt files will then be replaced with clean versions.

To reset your device to its factory settings, follow the steps below:

1. Backup your device's data to any cloud storage service (e.g. to Google Drive, Dropbox) or your computer;
2. Go to Settings, tap on Reset and tap on the factory reset option;
   
   

The tutorial below demonstrates how to reset your device (taken on a Samsung Galaxy device, running on Android 8 - the steps described may vary from one device to another):

Note: Make sure that your device is fully charged before resetting it, to avoid additional complications. Also, do make a backup of your personal files (photos, videos, music, and other documents), so that they are safely stored.