So I am trying to use reusable templates and I get this to work on your sandbox, but not on my site.
Check page https://darienlionsclubofgeorgia.org/causes/
Then edit with Oxygen and as you can see the reusable template is in the inner section.
Also, my 404 template is an issue as well.
I made a 404 template (per the web tutorials) and that seems to not be working.
I did it on the sandbox with no issues.
You can leave a reply here or ask me questions also.