Thousands of websites have become broken since WordPress 5.5 shipped without a JavaScript library called jQuery Migrate. We've updated all of our themes and now they are compatible with WordPress 5.5. 

Follow our instruction to make your site work perfectly again:

1. Update your site to the latest version of the theme - we have done the job to be sure our themes are compatible with  5.5 
2. Install Enable jQuery Migrate Helper to fix the problem
3. Clear cache and reload your site.

Problem solved.