The pro builder is not loading on our site due to an issue with the protocol mismatch. It is multisite, and we noticed that in the installation, the base URL and site URL was set to HTTP for the parent site while installation, while the site is SSL secured. So, for the Pro Theme, they show the preview using the base URL, and it is getting redirected to HTTPS causing it to show a mismatch error with HTTP and HTTPS in the site.
We were able to make the changes in the subsite(https://give5program.org/springfield/) from the Network Admin > Sites > Edit page and changing the base URL and site URL. So the original issue was rectified. However, we would still get the error with the Pro theme on the parent site(https://give5program.org/), as we are not able to change the base URL and site URL from the admin panel.
We tried certain suggested methods such as performing a search and replace in the database tables for making http:// instances into https:// in various entries and by defining WP_HOME & WP_SITEURL in the wp-config.php file, etc. None of them worked so far. Can you please let us know what exactly is the cause of this issue with a possible solution?