Getting " invalid_grant" error when trying to use oauth with DigitalOcean gem in my rails app

Hi,

I’m using Rails 4.2.3. I’m trying to enable external authentication via DigitalOcean, using the tutorial but I”m running into some problems. I have registered my application with DigitalOcean (using the callback http://localhost:3000/users/auth/digitalocean/callback) and gotten my client ID and secret, which I have added into config/initializers/devise.rb

    config.omniauth :digitalocean, “myid”, “mysecret”
    config.omniauth :google, “Myid”, “MySecret”

and I have added the callback to app/controllers/callbacks_controller.rb

def digitalocean
    @user = User.from_omniauth(request.env["omniauth.auth"])
    logger.debug "user: @user"
    sign_in_and_redirect @user
end

However, when I link to DigitalOcean from my application home page and then click on the “Authorize Application” from this page on DigitalOcaen’s site — https://cloud.digitalocean.com/v1/oauth/authorize?client_id=myid&redirect_uri=http%3A%2F%2Flocalhost%3A3000%2Fusers%2Fauth%2Fdigitalocean%2Fcallback&response_type=code&state=b97390521c4edf54c6331d849fb8597dc6c15795c0cbfe8c , I am getting this error in my log

E, [2016-01-24T14:56:26.493450 #36584] ERROR -- omniauth: (digitalocean) Authentication failure! invalid_credentials: OAuth2::Error, invalid_grant: The provided authorization grant is invalid, expired, revoked, does not match the redirection URI used in the authorization request, or was issued to another client.

What do I need to configure where to allow things to work properly?