I'm unable to access the instance of virtuoso at http://app.approovia.net:8890/

The person in charge of managing the instance has confirmed that it’s working properly on his end. So what could be the issue?

Please use a network tracer to determine what wrong.

For example, open up your browsers inspector; got to the “network” panel, and then attempt to make a connection. That will provide a network trace regarding what’s happening over the wire.

Alternatively, execute:

curl -IL http://app-approovia-net:8890

/cc @Joshua

use this @Casido
https://app.approovia.net/

It’s working now. Thanks.