How to fix "markup must be well-formed" error in xml-document

Question

I'm just starting with xml and tried to follow a tutorial. I managed to write my own xml-document, but always get this error in line 7 when I try to validate the file: "The markup in the document following the root element must be well-formed." I tried a lot of different solutions, but nothing worked. Here's the document:

    <?xml version="1.0" encoding="UTF-8"?>
    <list>
        <user>
            <name>Peter</name>
            <score>7</score>
        </user> 
        <user> 
            <name>John</name>
            <score>10</score>
        </user>
    </list> 

Sorry for my bad english, I'm not a native speaker and thanks for any help.