You cannot enter planned values with activity &

What causes this issue?

Your data is to be transferred via activity &v1&. With automatic data
transfer, only those activities can be processed with which you can also
enter planning data online. You cannot enter planning data online with
the specified activity.

System Response

Processing for the document is cancelled.

How to fix this error?

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

Error message extract from SAP system. Copyright SAP SE.