Getting 404 when loading in my browser

Per the instructions at Linux Installation | Stardog Documentation Latest

$ curl | apt-key add
$ echo "deb stable main" >> /etc/apt/sources.list
$ apt-get update
$ apt-get install -y stardog=<version>

However I am getting this error:

Could not resolve ''

And indeed when I point my browser to - getting:

404 Not Found
Code: NoSuchKey
Message: The specified key does not exist.
Key: deb/index.html
RequestId: YP3W4VXBT92X0H2N
HostId: 5hcla9TEYn5vAVW7R2IMlE8ajOBQuIBP0w/aLEELsuCHOXOuI6l2WF/c0hTeA4OTWfe3IRkIzNk=

What is the problem?


It works now - apt-get update - even though the above url still gets 404