Thanks for contacting us and choosing our product!
First of all we see your support time has been expired, so you should renew it to continue get support in the future.
We checked backend of your site and see you are using HTTPS but not complete setup and it make many files can’t read: https://prnt.sc/j3RksMQJtLIM
and it cause the issue with image select of Metabox plugin.
So in this case you should fix the issue with HTTPS first. You can don’t know how to setup HTTPS on your site you can contact your hosting provider.
We have just reinstall Meta box plugin and clear caches.
And it’s working fine now: https://prnt.sc/OQ27vp95W5WM
So maybe you need to clear caches to see changes.
Also your support time has been expired, so you should renew it to continue get support in the future.
Hope this helps!