To make fancybox works I had to add the code below to _config.php file

SSViewer::setOption('rewriteHashlinks', false);

That cause Anchor tag - link to in same page not working properly.
ex)

<a  href="#aaa">Link</a>
....
<a  name="aaa">Jump to here</a>

Now #aaa not take me to "Jump to here" in the same page but take me to mydomain.com/index.php/#Contact

What is the best way to fix this issue?

Thanks