64 bit APK generated cannot be installed

I would like to ask for help coz I am having issues with the apk generated for 64bit and it cannot be installed on the device. The installation fails. I am using the latest harman sdk and even have license. I already followed every step to create a release. I am able to generate the apk but the apk fails to install. I am already stuck with this issue for almost a month but still no luck. Please help me ASAP. Thanks guys.