Copy and Paste Append Query Error

I am attempting to copy and paste an append query within the same data base.
When I paste it and type in the new query name I get the following error
which appears to be more related to a table error. Very confused. Any help
would be appreciated.

The changes you requested to the table were not successful because they
would create duplicate values in the indes, primary key or relationship.
Change the data in the field or fireds that contain duplicate data, remove
the indes, or redevine the index to permit duplicate entries and try again.