I have customized the code and created the release apk with new keystore file. Finally the mobile.apk in mobile service is repleaced with newly created mobile.apk (release). then i have downloaded the file to mobile ( debug mode is activated ) but when i trying to install i got below error.

So i googled this issue and found that it needs to register with below Play Protect Appeals Submission Form. But when i try to install RnD released apk, i dont get this error. Could you please let me know how RnD did this? how RnD get rid of this issue? do RnD register with this?