Exception when indexing pdf document

Hi David, It prints the error ..

{ "error" : { "root_cause" : [ { "type" : "exception", "reason" : "java.lang.IllegalArgumentException: ElasticsearchParseException[Error parsing document in field [data]]; nested: IllegalArgumentException[Illegal base64 character a];", "header" : { "processor_type" : "attachment" } } ]