Using ruby curb gem to access paypal api
I can't tell you exactly what's wrong, but I can tell you how to see what's happening. Try putting it into verbose mode, so you can see what data and headers are actually being sent:
curl = Curl::Easy.new# Make it verbose, prints to stderrcurl.verbose = truepaypal_result = curl.http_post("https://api.sandbox.paypal.com/v1/oauth2/token", "grant_type=client_credentials") do |http| # etc.endYou can compare with the CLI version by using the -v flag.
Hope that helps you discover the difference.