Specify a project definition, WBS element, or network/activity

What causes this issue?

Possible causes:
Sender specification incomplete
Sender specification unclear

System Response

How to fix this error?

You can specify one of the following combinations:
Project definition - Possible with orders
WBS element - Possible with hierarchy and with orders
Network number - Additional restriction to one activity possible

Error message extract from SAP system. Copyright SAP SE.