I’m trying to implement Gmail OAuth authentication in my Android app but running into some problems. I downloaded a sample project from GitHub and added the necessary OAuth libraries including the signpost jar files (commonshttp4, core, and jetty6 versions).
The app builds without any compilation errors, but when I launch it and try to authenticate, the Gmail login screen doesn’t show up at all. Instead, I just get an “Unauthorized” response status message.
Has anyone experienced this before? I’m not sure if it’s a configuration issue with the OAuth setup or if I’m missing something in the implementation. Any help would be appreciated.
your oauth callback’s probably wrong or the client id doesn’t match your app signature. double-check you’ve got the right package name in google console and verify your sha1 fingerprint - that’s what usually kills the auth flow right off the bat.
Had this exact issue two years back when I first set up OAuth. No login dialog usually means your auth request isn’t hitting Google’s servers right. First, double-check your OAuth scopes - I’ve seen broad scopes fail silently. Next, make sure your package name in the code matches what’s in Google Cloud Console exactly (caps matter). What got me was using the wrong API key or accidentally grabbing the server-side client ID instead of the Android one. You need the Android client ID from your google-services.json file when you initialize GoogleSignInOptions.
Last year, I faced a similar issue with OAuth in my own app. If you’re getting an “Unauthorized” message without seeing the Gmail login dialog, it often points to a misconfiguration in your OAuth settings rather than a problem with the library itself. It’s crucial to verify that your Google Cloud Console is correctly configured, especially ensuring that your client ID for Android matches. Also, don’t forget to use the SHA-1 fingerprint from your debug keystore in the console.
The redirect URI must match exactly what’s specified in your manifest file, and it’s important that the Gmail API is enabled for your project, alongside proper configuration of your OAuth consent screen. So, if the login prompt is missing, that suggests the auth flow can’t initiate properly. Double-check these aspects to resolve your issue.