Thank you for writing in, can you confirm that you updated everything? WordPress, Theme, and the Under Construction extension. You can refer for the latest supported versions here.
If you find something that is not up to date, please update it.
Remember to clear all your caching features (plugin, server-side, CDN, and browser’s cache) after updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
If you can confirm everything is up to date and the issue persists, please provide us login credentials in a secure note so we can take a closer look.