Discussion: OAuth2 fatal error: bad_redirect_uri troubleshooting

I've checked thoroughly that my auth redirect urls are exact matches:
Redirect URI: http://caffeine.csclub.uwaterloo.ca:4567/auth
Generated Link: https://api.glitch.com/oauth2/authorize?redirect_url=http%3A%2F%2Fcaffeine.csclub.uwaterloo.ca%3A4567%2Fauth&response_type=token&client_id=<api_key>

But I still receive the bad_redirect_uri error. What are other possible causes?
it needs to be the exact same "string". add "http://" to the redirect uri in Glitch.
Sorry, the forum post reformatted the link. The http:// is explicitly in my settings as well.
I think you are using REDIRECT_URL ... and it is REDIRECT_URI (redirect_uri)
I think the port might be conflicting.
I have a test App using a "port" in the uri... I think he/she used "_urL" instead of "_uri"