# Oauth error invalid_request: The redirect_uri is not whitelisted (Shopify app install)

Installing a shopify_app Rails app in a dev store fails on the OAuth step with this error. The app ran on YOUR_HOST behind ngrok, and the redirect_uri parameter sent during installation did not exactly match any URL in the Partners dashboard whitelist. The mismatch can be subtle: a different ngrok subdomain, http vs https, a trailing slash, or a double slash (e.g. ...//auth/shopify/callback) caused by a trailing slash in the app host env var.

## How to handle it

Copy the exact redirect_uri value from the browser address bar on the error page, URL-decode it, and add that exact string to Partners dashboard > App setup > Allowed redirection URL(s). Multiple URLs are allowed, one per line, so whitelist both YOUR_HOST and your ngrok URL, and match the scheme exactly (http vs https both need entries if both are used). Watch for trailing slashes: a trailing slash in your app host variable can produce a double slash in the callback path and fail the match. The reporter confirmed the install worked once the exact redirect_uri was whitelisted. Source: https://github.com/Shopify/shopify_app/issues/486