Views of type & are no longer supported.

What causes this issue?

Structure views and entity views (type E) may no longer be created.

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?

Please create a structure instead of a structure view.
Views which are assigned to an entity should generally be created as
database views.

Error message extract from SAP system. Copyright SAP SE.