DTL record testing error

In the Data Transformation Builder, I have a source record with several values that is connected to a target record with several properties. In the Tools tab, clicking on Test, I have an xml format set up to test the data transformation but I'm getting this error:

ERROR <Ens>ErrNoObjFromString: Failed to find element Record / class BI.process.prodTest.Record in String

Do you know what might be causing this error to happen?