SAP Message WD291 - Container element & is not multiline -> Appending not allowed

Diagnosis
You are trying to append values to container element &V1&. This is notpossible, because the container element is not defined as a multi-lineelement.

System Response
Appending values is only possible for multi-line elements. For othercontainer elements, only the assignment operator can be used.

Procedure
Enter a multi-line element as the result element for the assignment oruse the assignment operator "=".