Processing Server cannot connect to Application Server. In EventViewer Windows Application logs the errors as below appear:
FlexiBr: Processing Server restart: Error creating an Application Server session: <Application server Url> (error code: (HTTP 407, 18, 0))
HTTP 407 is a general HTTP error 407 Proxy Authentication Required. The issue occurs because proxy settings in the environment block the connection from Processing Server to Application Server over HTTP/HTTPS.
Proxy settings between Application Server and Processing Server should be adjusted to allow the connection over HTTP or HTTPS.