Could the solution to this simply be adding a CORS policy to your servers to allow retool-edge.com? Hard to see how that would be a security hole as is its basically the same thing typically done when a site allows CORS with its own api.domain.com
Hey there! As a security measure, Retool runs all custom JavaScript on a separate sandboxed domain. Self-hosted orgs can set this domain with the SANDBOX_DOMAIN environment variable, but for Cloud hosted orgs it will be retool-edge.
Different browsers handle cross-origin requests differently, it looks like this may be a result of CORB or something similar since the linked JSON seems to work for me in Firefox but not Chrome. I'm not familiar with Stimulsoft and could be wrong but, unfortunately, that might mean that it's not supported in Retool at the moment.