What's wrong with this nested list?
<ul> <li>Item 1 <ol> <li>Sub-item 1<li> </ol> </li> </ul>
Missing opening <ol> tag for nested list
<ol>
No issue
Should use <ul> for nested list instead of <ol>
<ul>
Missing / in the closing </li> for "Sub-item 1"
/
</li>