Differing settlement types

What causes this issue?

Several tours shall be settled together although the settlement types
differ. A common settlement is not possible in this case.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Change the settlement types in the relevant torus or do not settle
these tours together.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.