Comment not terminated
A comment is not closed with -->, or contains --.
The message, as the validator reports it
Comment not terminated
Why it happens
- A missing
-->: the comment then runs to the end of the file. - Two hyphens inside a comment (
<!-- a -- b -->), which XML forbids: Double hyphen within comment.
How to fix it
Close the comment with -->, and do not use -- inside it.
Example
Reports the error
<note><!-- todo </note>
Fixed
<note><!-- todo --></note>