This means your instance is launched as an onion site, and as such, cannot be viewed or accessed with a non-tor browser.
Onion sites can only be accessed through tor-browsers, but if you want your discourse instance to be accessed outside its onion domain, then you will need to get a premium domain for the ‘surface web’ like a .com,.org, .ly, etc. When you do this, then you can map the domain you bought with your discourse instance through its IP address.
I hope this is clear enough, huh?