For many of our clients, we provide integration with a CRM. One of the more popular CRMs that we support is Salesforce. When building contact forms and calls to action, we leverage the popular WordPress plugin Contact Form 7 along with the the 3rd-party Integration plugin.
Recently, all of the Salesforce integration endpoints stopped working. It was a bit of a head scratcher but after some detective work, we discovered that Salesforce had changed the integration endpoint. More details on this change can be found here.
To make this change, login to your WordPress admin and goto Contact->3rdparty Services->Salesforce
Hope this helps someone else in need.