I hope you are well today and thank you for your question.
I could confirm the issue on your website but the search is working fine on my site using the latest version of the Ivory Search plugin so it seems your website specific issue.
This can be due to plugin conflict on your site so please try temporarily deactivating all plugins except the Ivory Search plugin and see whether everything works fine, and then enable the plugins one by one to see which plugin is conflicting if any.
Also, This can be a theme issue used on your site so to confirm it just temporarily use the Twenty Twenty One theme on your site. If everything works fine then it’s your site theme issue.
Best regards,
Ivory Search Support