There's a known plugin conflict between divi theme/plugin and domain plugging that prevents the visual builder from not loading on the front end.
On a multisite installation that has a domain mapped subsite, the divi front end visual builder will not work.
Factors to consider when replicating the problem
Original domain must have SSL wildcard
Force SSL using original domain on admin pages & login pages must be enabled
Force SSL on (unmapped) subsites on the front.
Please fix asap.
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