Table of contents
The XML document has content outside of tags and it is defined by the schema that only elements are allowed.
Hello Mr. <to>Andersson</to>
How is your <system>Matrix</system> doing?
Sincerely Yours, <from>Agent Smith</from>
would produce this error.
(PS. this is possible in XML and XML schemas by setting complextype attribute mixed="true" but bank materials do not allow this.)
Explanation of the error message given by the validator: