Redirect URI Mismatch: How to Fix Google OAuth Errors

What is redirect URI mismatch?

When you use Connect with Google (OAuth) in EmaReach, Google redirects the user back to your app after sign-in. The redirect URI is the URL Google sends them to. If that URL does not exactly match one of the Authorized redirect URIs in your Google Cloud OAuth client, Google shows an error (e.g. "Redirect URI mismatch" or "Error 400: redirect_uri_mismatch").

Why it happens

• The URI in Google Cloud was typed by hand and has a typo or wrong path.
• The URI in Google Cloud uses http instead of https (or the wrong domain/port).
• EmaReach’s callback URL changed (e.g. after a domain or config change) and Google was not updated.

How to fix it

1. Get the exact URI from EmaReach

   • In EmaReach, go to Settings → Integrations → Gmail.
   • Open the form where you enter Google Client ID and Client Secret (or "Add your Google OAuth credentials").
   • On that page, EmaReach shows the Authorized redirect URI you must use. Copy it exactly (including https, domain, and path).

2. Update Google Cloud Console

   • Go to Google Cloud Console → APIs & Services → Credentials.
   • Click your OAuth 2.0 Client ID (Web application).
   • Under Authorized redirect URIs, add the URI you copied from EmaReach (or replace the wrong one). Do not add extra spaces or characters.
   • Save.

3. Try again

   • In EmaReach, click Connect with Google again. The sign-in and redirect should complete without the mismatch error.

Important

• Copy from EmaReach, don’t type. The URI must match character for character.
• If you have multiple environments (e.g. staging vs production), each has its own redirect URI; add each one in Google Cloud if you use both.

Summary

Copy the Authorized redirect URI from EmaReach (Settings → Integrations → Gmail, when adding credentials), paste it into your Google Cloud OAuth client’s Authorized redirect URIs, save, then try Connect with Google again.