Installation silently blocked for Android release build signed APK when testing App update

Question

When I try to update my app (installing signed APK with higher version manually on app already installed from playstore), it is not being installed (" App not installed") and shows the following error in Studio :

I/Finsky: [1144] com.google.android.finsky.verifier.impl.en.c(263): Verifying id=8, result=-1
I/Finsky: [1144] com.google.android.finsky.verifier.impl.dq.a(37): 
Installation silently blocked for com.somename.somename
I/Finsky: [1] com.google.android.finsky.verifier.impl.en.c(139): Verification 
complete: id=8, package_name=com.somename.somename
V/ActivityThread: SVC-Destroying service 
com.google.android.finsky.verifier.impl.PackageVerificationService@995aa6e
V/ActivityManager: Broadcast: Intent { 
act=com.android.packageinstaller.ACTION_INSTALL_COMMIT flg=0x10 (has extras) 
} ordered=false userid=0 callerApp=null
V/ActivityManager: Broadcast: Intent { 
act=com.google.android.gms.safetynet.action.HARMFUL_APP_BLOCKED flg=0x10 } 
ordered=false userid=0 callerApp=ProcessRecord{6b6f45e 
1758:com.google.android.gms/u0a13}
D/InstallAppProgress: Installation error code: 3

where com.somename.somename is my package name.

The app which is live on playstore is signed with v1 signature, & the newly generated signed APK is also built with v1 signature.

compileSdkVersion 23 buildToolVersion 26.0.1 targetSdkVersion 23

For SDK Versions >= M I checked "Apps" in "Settings" to try "Uninstall for all users", but the app wasn't listed there (hence was uninstalled completely)

For SDK Versions < M It was able to update for 1 time but repeating the same process was a failure.

The APK is installed successfully if not previously installed.

Answer 1

I faced the same issue recently. Seems like it was caused by the latest Google Play update. My app was successfully installed on the device with Android 8 but failed to install on Android 7.

Going to Google Play -> Play Protect and turning off Scanning device for security threats helped me.