I'm struggling after having installed a Qlik Sense server, as it seems I'm unable to access it from outside the company.
I double checked to have added the IP address to the whitelist, restarted the services, added the IP to the trusted zones but nothing succeeded. I get the (strange) error you can see in the enclosed screenshot.
Just a guess. But when you are coming in from outside the network you are the user Anonymous. There are many security rules in the QMC that limit what the user Anonymous can do and see. So you may be getting blocked there if everything else is setup correctly.