How to fix error code 944 on Google Play Store (Nothing else worked)

If none of the other solutions worked, reset your device to its factory settings, to remove the corrupted system files from your device. 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, etc.);
2. Go to Settings and on General (management);
3. Tap on Reset;
4. Tap on the factory-reset option you prefer most (available options vary from one device to another);
   
   

Feel free to watch the tutorial below, on 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 you can restore them after the reset.

There is a possibility that the latest version of the Google Play Store app caused the error code 944, maybe because it was downloaded improperly. In this case, it's better to revert the Google Play Store app to the default version, following the steps below:

1. Go to Settings and tap on Application Manager/Apps;
2. Tap on Google Play Store, and select Uninstall updates;
   
   
   
   
3. Tap on OK to confirm; 
4. Open the Google Play Store app;
   
   

Here is an video guide on how to uninstall updates (taken on a Samsung Galaxy device, running on Android OS 8 - steps may slightly vary from one device to another):