"error":"invalid_grant","error_description":"invalid authorization code" in salesforce

Question

I have setup my 'Salesfore' connected App for 'OAuth' using which I am able to authenticate user. For subsequent request I am trying to get access token hence posting values to Salesforce as below.

$.post("https://login.salesforce.com/services/oauth2/token",
                {
                    "grant_type": "authorization_code",
                    "code": "00DXXXX5",
                    "client_id": "3MVXXXXK",
                    "client_secret": "15XXXX4",
                    "redirect_uri": "https://mysit11e.com/SalesforceCallback.aspx"
                });

but unfortunately I am having an error

"error":"invalid_grant","error_description":"invalid authorization code"

I have made sure there is not % symbol is not present in code hence replaced %21 with !.

What else shall I try to get this working.

Answer 1

you appear to be posting it as json try posting it as a request string

grant_type=authorization_code&code=00DXXXX5&client_id=3MVXXXXK&client_secret=15XXXX4&redirect_uri=https://mysit11e.com/SalesforceCallback.aspx