Diagnosis
You have selected and action which is possible only with early numberassignment

System Response
Action not executed

Procedure
Either switch on early number assignment or define a follow-on actionusing the same function module called in the action box follow-onfunction.
Path : spro > Plant Maintenance and Customer Service > Maintenance andService Processing > Maintenance and Service Notifications >Notification processing > Additional Functions > Define Follow-UpActions for Tasks
Assign the follow-on action to a task catalog ( catalog type : 2)
Path: spro > Plant Maintenance and Customer Service > Maintenance andService Processing > Maintenance and Service Notifications >Notification Creation > Notification Content > Maintain Catalogs
Ensure that the follow-on function for the notification type is switchedoff by selecting the Task mode for the action in its "Usage And" field.
Path: pro > Plant Maintenance and Customer Service > Maintenance andService Processing > Maintenance and Service Notifications >Notification Processing > Define Action Box > Define Follow-UpFunctions (Generated Tasks/Activities) > Notification Types > Activities: Details