Contacts not coming through to Constant Contact from my website

I am getting the following error when I run the syncconstantcontact.v3.php script.:

error_description":"refresh_token parameter is required for grant_type=refresh_token","error":"invalid_request

It appears there is an issue with the code in getaccesstoken.v3.php since I am getting the following error:

"error_description":"Authorization code is invalid or expired.","error":"invalid_grant"

How do I solve the issue with the expired Authorization code?

Running the first code above should sync contacts in my database with constant contact but that is not working now.