I have a problem with a validation error to http://www.tsiapos.gr/ (Joomla 3.9.10 - yootheme template0
which is related to empty link in "offcanvas"
<a href="#offcanvas" class="uk-navbar-toggle uk-visible-small" data-uk-offcanvas=""></a>
I don't know where to find the code and how to fix it. Thank you.