Classify Document Scope: Method not found

Hello everyone,

Can you help me about this problem?
Classify Document Scope: Method not found: ‘System.Collections.Generic.List`1<UiPath.DocumentProcessing.Contracts.Dom.Metadata> UiPath.DocumentProcessing.Contracts.Dom.Document.get_DocumentMetadata()’.

I’m trying to make a keyword for classifier a .pdf document using OCR with the activity Keyword Based Classifier. The error output is look like a description above.

The screenshot of keyword configuration at below.

Thank in advanced, Regards
Brian H