Implementing Github authentication with Firebase and Xcode (swift) -

i've been receiving error "an internal error has occurred, print , inspect error details more information" when trying login through access-token receive github.

let credential = firgithubauthprovider.credentialwithtoken(accesstoken)                         firauth.auth()?.signinwithcredential(credential) { (user, error) in                             if let error = error {                                  print(error.localizeddescription)                              }                         } 

it seems issue happening here i'm not sure why. thank in advance!