Blur UMG Not working on Android

I wonder if that effect requires Mobile HDR. Check your project settings and make sure Mobile HDR is turned on, click the green Restart button, and then try building to your Android device again from there and let me know if that helps. I’m just guessing because I know a lot of rendering features don’t work without Mobile HDR enabled. Turning it off gives you faster performance and you might especially want it off for things like Paper2D projects where you don’t need it in general, though. But a lot of things don’t work with it on.

Also check your project settings: Target Hardward setting. Changing the Maximum/Scalable and Mobile/Desktop buttons there will give you a list of features that will be turned on/off with the new setting.