Zendesk Chat OAuth url returns Internal Server Error

I want to use Zendesk Chat OAuth. I have created an API client for it, but when trying to access this url https://www.zopim.com/oauth2/authorizations/new?client_id={ClientId}&redirect_uri={redirectUri}&response_type=token&scope=read write it returns me this:

Same thing happens if I use OAuth with code instead of token.