Web API PKCE Authorize Not Working: INVALID_CLIENT: Invalid redirect URI

[Aceee3]

Plan

Premium

Country

USA

Device

Pixel 3a Emulator

Operating System

Android 13

My Question or Issue

I am developing a mobile app with flutter/dart that uses Spotify's Web API. I am able to authenticate users without PKCE but when I use PKCE I get the error "INVALID_CLIENT: Invalid redirect URI" yet I have not changed the redirect URI and the URI used in the request matches the URI in the settings in my developer portal. Do I need to do anything other than use the parameters code_challenge_method and code_challenege to use PKCE?

Here is an example of the authorization URl I use:

https://accounts.spotify.com/authorize?response_type=code&client_id=[My Client ID]&scope=user-top-re...

Query Parameters:

response_type: code

client_id: [My Client ID]

scope: user-top-read+user-read-recently-played

redirect_uri: com.example.abc-spotify%3A%2F%2F

state: kDHp9NZjWbYD

code_challenge_method: S256

code_challenge: 877811825597e44c2a3f38f2ea615370212d32a3837c1e98bec67f1b103be88b

This was the code verifier in this example: ueA7xfrl9hB8Q8jPBzvxHL0ldxzjPN5PWCGnG8pbtw7Gmlin9nyBXw2l4hFc6rDQflcUmAbbe72bURkY5QAfErDsKjDZ1x3P9glG