Hello,

I have deactivated all the plugins not related to the theme: https://prnt.sc/us3t9w

I have added a template successfully: https://gyazo.com/9ba4cca02c024899c0aeb502f5fe5828 you can see this template in 360 degree page.

Now I activate the plugins as they were not to keep the site without them.

Deactivate ALL plugins. Then go to Appearance > Install plugins and activate all, so your would get this set https://prnt.sc/us3t9w

Then activate your plugins one by one checking the template library to detect which one causes the problem.

Best Regards