This error is reported if you try to transfer elements in Test Designer below the allowed hierarchy level.
Error message
In this project additional hierarchy levels are not allowed.
Cause
When creating a user-definable test project, the maximum number of hierarchy levels (levels 1-12) is defined.
For projects of the SAPĀ® Solution Manager type, a maximum number of four levels is allowed (Project/Scenario/Process/Process step).
Solution
Insert the model one level higher.
Transfer it to a test project in which a higher maximum number of hierarchy levels is defined. If required, create a new test project in which you define a higher assignment level.