Salesforce is retiring the routing of www.salesforce.com as the API endpoint as of January 1st 2016. This is specifically impacting anyone using the PDI Salesforce step.
How is that impacting you?
Starting from January 1st, 2016, transformations with the Webservice URL set to "www.salesforce.com" will need to be changed to "login.salesforce.com"
What will happen if I do not take action?
The API will no longer function, and your API calls will result in a “404 (Page Not Found)” error.
Details can be found here: