Android - Why is Play Store showing "Can't install app...Error Code: 910"?

I had been getting error 910 for days. I finally managed to solve the problem using the following steps:

I "ejected" the SD card via settings, device, storage. I didn’t physically need to remove the card from the phone.

(Android 6.0.1..... Blackberry Priv.)

I had the same problem after trying to upgrade my Snapchat app to the alpha version following a tutorial on the XDA developers forum. After finishing the tutorial, the app wouldn't uninstall, run, or reinstall properly. The solution (for me) was to uninstall the broken app using ADB.

1. Install adb (if you haven't already).
2. Enable developer mode on your phone (if you haven't already).
3. Type adb devices into the terminal / command line.
4. Tap 'yes' on the authorization prompt on your phone (if you haven't already authorized).
5. Type adb uninstall <insert package name here> to uninstall the broken app.
6. You can now reinstall the app from the Play store or wherever you got it from.

Unfortunatly none of these solutions worked for me. So I have downloaded latest Youtube apk from third party site and installed successfully. App is working fine. But in Play store it is still showing my earlier version app and asking to update. I guess hereafter every time I need to update from apk only.