Hello everyone, and well done for what you do. Template Investa Rel. 1.0.2 on Joomla ver. 5.2.4

As soon as I enter the template management section, without making any changes, the site menu disappears. I don’t understand why, and I can’t manage to restore it.

Any idea why? Any suggestions? My site is currently running in a local environment. A warm greeting from Italy. Renzo