Hello, I sent an email last Friday morning and have not received a response. ... View more

I have built an integration that was refreshing tokens every 30 minutes for 2 months, then yesterday it stopped working.   I get the same message:  "response": { "error_description": "Invalid client or client credentials", "error": "invalid_client" }   In the code, I am setting the Authorization header: 'Authorization: Basic ' . base64_encode($request['api_key'] . ':' . $request['secret'])   When I check the API key in the API Reference it works. Also, I have triple checked the API Key and Secret. I am able to complete steps 1-4 of the workflow: https://v3.developer.constantcontact.com/api_guide/server_flow.html   But step 5 is breaking... not sure what could be wrong. ... View more