Hello,
I have enabled default WordPress theme and see the same problems even when all the plugins are disabled. You can enable default theme in Appearance > Themes and check by yourself. Seems this is something with your WP installation. I see that you have WP-Optimize plugin in the list of installed plugins. Maybe you have optimized something wrong and it caused the issue.
Anyway, we can help you only in case problem is related to theme files but if default WP option – menu – does not work with default WP theme we can do nothing because default WP options are out of the scope of our support.
Regards