SAP Message RSBC201 - You cannot select field &1 in the source

Diagnosis
The check for data transfer process &v2& produced an error. The cause ofthe error is that you cannot select field &v1& in the source.
When the data transfer process was activated, the object could not beselected and was therefore deleted from the source.

Procedure
Delete the selection condition for this field in the data transferprocess. Delete the corresponding row in the maintenance of the datatransfer process filter.