Getting Invalid_request error using Oauth 2.0 policy for generating authorization code

[#1]

Im using the following configuration for generatin auth code:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<OAuthV2 name="OAuthV2-GenerateAuthorizationCode">
<DisplayName>OAuthV2: Generate Authorization Code</DisplayName>
<ExternalAuthorization>false</ExternalAuthorization>
<Operation>GenerateAuthorizationCode</Operation>
<Scope>scope</Scope>
<ClientId>client_id</ClientId>
<ResponseType>code</ResponseType>
<ExpiresIn>600000</ExpiresIn>
<SupportedGrantTypes/>
<Tokens/>
</OAuthV2>

where scope=openid and client_id=my developer's app client_id

This configuration is giving me invalid_request error(500 error)

Any help would be appreciated 🙂