There is a bad authentication interaction between ArcGIS Workflow Manager (WMX) and Portal for ArcGIS with Public Key Infrastructure (PKI), while using a third-party proxy server. When a third party proxy is set within ArcGIS Workflow Manager to be used for Data Store settings, the error "The username does not exist in the system.", subsequently followed by "Unable to update user store setting. Unable to add current user as an administrator."
Duplicate of BUG-000115300: The underlying issue is described in BUG-000115300.
対処法
The only way to remedy this issue is to use the actual Portal Uniform Resource Locator (URL) and not the Proxy Server being used.When workflow succeeds = https://supt0003855.esri.com/portal