Drawloop - Error: The request sent to this API connection does not have a correct salesforce.com URL
An error of "The request sent to this API connection does not have a correct salesforce.com URL. Please have your salesforce.com administrator contact support." is received after updating to Salesforce Spring '18.
Navigate to Setup-->Critical Updates
Please ensure the following Critical updates are deactivated:
"Remove Instance Names From URLs for Visualforce, Community Builder, Site.com Studio, and Content Files"