In release mode, my google sign-in is not working, but it works fine in debug mode. I got a similar question from SO here, but I didn't get perfect solutions.
My handleSignInResult is coming false - How can this be fixed?
Make sure you follow all the steps specified in the Guide
. If need be, create a new OAuth Client, new configuration file (the google-services.json) file and do everything step-by-step.
Also try adding a Web Client giving the same credentials. And for Android as well as Web client give both the SHA1 for debug as well as the release keystores. In Android Studio, at extreme left you will see a tab saying "Build Variants". Select the release mode there and do everything after that.