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Firebase google authentication not working android

Posted by: admin May 14, 2020 Leave a comment


I migrated my old google sign into firebase authentication. google login properly for old version supporting google, but for firebase auth, I am getting DEVELOPER_ERROR.

I also tried adding a SHA-1 key to the firebase console, but I’m getting this error:

An OAuth2 client already exists for this package name and SHA-1 in another project.
You can omit the SHA-1 for now and read more about this situation and how to resolve it

Again the possible solution for this is to whitelist the client id. I followed this guide but it won’t helped me,I’m still getting DEVELOPER_ERROR.

How to&Answers:

You can’t have two projects of same package name. Even if you delete it. It will take at least 4-5 days to get deleted fully from developer’s console.

So one solution is generate a new SHA-1 key by custom signing the app by generating a signed apk from android studio. Or just create a new project with different package name both ways will work for now.

Hope this info helps. Do let me know if it changes anything for you.
I encourage you to go through these official Google docs on signing apk 1 to understand this process.


The error says itself that you already have a project in google console. As you were using old google login, your project and auth key was created for that package name in google console. Delete the newly created project from firebase and then while adding click on import project from google console. This will import your project from google console and add it to firebase with the old auth key and sha-1. Download google-json and follow the guidelines to set up the project. Then only you will be able to login using firebase.