SAP Message RP066 - Enter either payee key or payee name

Diagnosis
You have entered both a payee key and payee data. The payee data youhave entered data does not correspond with the data stored for thepayee key.

System Response
The system cannot store this data due to inconsistency.

Procedure
Please enter only the payee key and delete the data in the payee textfield (the data stored for this payee key is then valid) or deletethe payee key and enter the payee data manually.