The problem was traced to the Windows Firewall. Once this was disabled (the company concerned had another firewall in use) the connection could be made with no further problems.
On the Agile server open the Windows registry with regedit.exe Find the following key HKEY_LOCAL_MACHINE\SOFTWARE\Serena\Agile Planner\WebServiceClients
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\AODSchedulerService Find this registry folder: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ Windows \CurrentVersion\Installer\Folders
On the web server open the Windows registry with regedit.exe Find the following key: Mariner/PPM -- HKEY_LOCAL_MACHINE\SOFTWARE\Pacific Edge Software\WebServiceClients