Flutter Android application is not installing after release signing

Question

If I build apk with debug signing config - everything is ok.

If I build apk with release signing config, where I use these in build.grade from docs:

def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

signingConfigs {
    release {
        keyAlias keystoreProperties['keyAlias']
        keyPassword keystoreProperties['keyPassword']
        storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
        storePassword keystoreProperties['storePassword']
    }
}

my application is not installing on a real device. I have uninstalled past debug installations.

I have generated the key and added key.properties file. I have my build successfully done, but apk is not getting installed with the corresponding popup. The message is "App not installed.".

I only tried to run flutter build apk command with --split-per-abi flag. The result is the same for every generated apk. And also tried to build an app bundle. Same.