Dwolla OAuth giving Invalid Client Id

Question

I'm trying to use the Dwolla OAuth feature, so I send the user to the following url:

https://www.dwolla.com/oauth/v2/authenticate?client_id=mydwollakey&response_type=code&redirect_uri=http://localhost//Payment/OAuthResponse&scope=send%7Ctransactions

The first time I send them there, it takes them to a Dwolla login page. Once they enter in their username and password and click Login, it gives them:

We were unable to authenticate you with Dwolla: access_denied Invalid client ID.

The client id is my Dwolla Key, which I'm sure is valid, as I'm able to make another call with it (register user) just fine.

After that, every time they go back to the url, it no longer takes them to the login page, it returns "We were unable to authenticate you with Dwolla: access_denied - Invalid client ID." right away.

Any ideas?

Answer 1

The issue ended up being that my dwolla key has a / and + in it, and I needed to UrlEncode it before passing it in the querystring.

Answer 2

Verify that your key has been associated with the correct permissions. I believe OAuth2 refers to this as "scope".