[SOLVED] Facebook: Error validating client secret


I’am trying to get the facebook authentication to work.
I get this error:
Error in OAuth Server: Failed to complete OAuth handshake with Facebook. failed [400] {“error”:{“message”:“Error validating client secret.”,“type”:“OAuthException”,“code”:1}}

iam running it on localhost:3000 and so is the site url and i have this oauth redirect http://localhost:3000/_oauth/facebook?close

any tipps or help?