SAP Message 62121 - Service charge key & has to be assigned to settlement company

Diagnosis
Every settlement company defines specific cost elements. These arelinked to service charge keys.
In this case, however, the system could not find a cost element for oneof the service charge keys.

System Response
The rental agreement cannot participate in the settlement.

Procedure
Verify your entry and correct it if necessary.
If your entry was correct, contact your system administrator.

Procedure for the system administrator
Check and correct the settings for the cost elements of the settlementcompany in Customizing as required.