Member or Type '{0}' contains multiple metadata entries with the name '{1}'. The metadata entries could be coming from the ...

Member or Type '{0}' contains multiple metadata entries with the name '{1}'. The metadata entries could be coming from the ExportMetadataAttribute or from a property of a custom metadata attribute. Either remove the duplicate entries or enable the metadata entry with name '{1}' to allow multiple entries via the IsMultiple property on ExportMetadataAttribute or AttributeUsage.AllowMultiple on custom metadata attributes.