I hope you are well today and thank you for your question.
Please make sure you have not only enabled comments in the theme settings but also enabled it in the site settings as described in the following page.
I could confirm the issue on your shared site but couldn’t reproduce it on my test site.
This can be due to plugin conflict on your site so please try temporary deactivating all plugins except Unyson plugin and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.
I resolved the issue on your site by unchecking the site option “Automatically close comments on articles older than” as shown in the attached screenshot which was selected in the site Discussion Settings.