Do not use the path expression closed using the element &1.

What causes this issue?

In the consumption CDS view, a path expression that is closed using an
element is used. Only a path expression that consists of one association
and is closed using an element is allowed.

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?

Remove the path expression that is closed using an element from the CDS
view.

Procedure for System Administrators

Contact the corresponding developer of the CDS view to correct the
error.

Error message extract from SAP system. Copyright SAP SE.