Thank you
Admittedly I am a little confused by your issue. Each of these menu items appears to open in either a PDF or a non Joomla51 template? Considering the large number of sub menu items, I notice some of the items appear outside of the browser window making the inaccessible. One option to resolve this is to reduce the line-height of your sub menu items. To do so, add the following to the Custom CSS field of your template settings...
Edit to taste.
.hornav > ul > li > ul > li, .hornav > ul > li ul > li > ul > li {
line-height: 26px;
}
Ciaran