Recently created keystore with keytool and Google Play will show this message after uploading apk. Did something change? Last year it worked flawlessly.
You uploaded an APK with an invalid signature (learn more about signing). Error from apksigner: ERROR (Jar signer private): JAR signature META-private uses digest algorithm SHA-256 and signature algorithm RSA which is not supported on API Level(s) 14-17 for which this APK is being verified
Edit: godot 2.1.5, private info is now hidden