android - Issue with unsigned apk installation in some devices, "App Not Installed" error

Question

I distributed my android app apk to set of users through test fairy. It is not getting installed on some devices. It is showing "App not installed" error after trying to install. I have set my minSdkversion to 21(Android 5.0-Lollipop) and targetSdkVersion to 28(Android 9.0-Pie) in my Gradle properties file.

Devices on which I'm having issue in installing

Nexus 6(android version 6.0)
One Plus 6T(android version 9.0)

Devices on which I'm able to install .apk file without any issue

Sony Xperia Z2(android version 6.0.1)
Google Pixel 2(android version 9.0)
Oppo Realme 1(android version 8.0)

I have tried uninstalling and installing multiple times.
I have tried clearing the package installer cache.
Gave permission to install apps from unknown sources.But no change.
Can someone tell me what should I do to resolve this issue?

标签： androidandroid-studioinstallationapk