No grammar constraints (DTD or XML schema) detected for the document

No grammar constraints (DTD or XML schema) detected for the document.

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE Context>
<Context>

Change out Context with whatever the root element name is.

参考：

1、https://www.rodneybeede.com/No_grammar_constraints__DTD_or_XML_schema__detected_for_the_document.html

2、http://stackoverflow.com/questions/4551783/no-grammar-constraints-dtd-or-xml-schema-detected-for-the-document