Indeed, it's ok, thank you very much Ciaran

Hello

May I suggest sending temporary administration access to your Joomla installation to info@joomla51.com and we will examine this issue further. For our reference please paste a link to this post in your email.

Ciaran

Thank you very much Ciaran :-)
I installed the new version of the template, still the same problem.
I bypassed the problem: system / configuration / system / debugging system yes
then
media file / cms / css / debug.css
line 90 I added display: none;

div # system-debug {
margin: 5px;
display: none;
}

Now the menu and the slideshow appear ;-)
??

Best regards

Hello

It is hard for us to say what may be causing this. It is an issue that has not been presented before. May I suggest sending temporary administration access to your Joomla installation to info@joomla51.com and we will examine this issue further. For our reference please paste a link to this post in your email.

Ciaran

Thank you, message sent to info@joomla51.com

Thank you

The issue appears to be related to your YT Shortcodes plugin. Disabling this plugin appears to resolve the issue.

Ciaran