Status:
Investigating
Custom visual development - access to external resources using domain-names with hyphens is broken.
When developing a custom visual that needs to access external resources you can white list domains to permit web access as per https://learn.microsoft.com/en-us/power-bi/developer/visuals/capabilitie...
If you've got a dash/hyphen in your domainname it's a complete blocker for external access. I worked around it using our Azure FQDN rather than the public domain, but it meant I had to wildcard *.azurewebsites.net rather than {guid-identifier-with-dashes}.azurewebsites.net
May not be a bug, but it's an omission/oversight IMO