I have several servers set up in a development pipeline, and have accordingly had our network team give them DNS names. So each gateway has a server name with the pattern <3 char site code>V<4 digit sequence>, and then a DNS record with the pattern IGN_<3 char site code>_.
As an example:
My dev server at site WHQ could be WHQV1234 with DNS name IGN_WHQ_DEV.
The DesignerLauncher successfully recognizes http://IGN_WHQ_DEV:8088 as a valid gateway and lets me add it; however, when I try to launch the Designer, it does not work (I get an error saying “Error launching application: UnknownHostException: null”). If I use the server name (so http://WHQV1234:8088) the Designer will successfully launch. Note that I can ping both server and DNS name, I can access Perspective sessions using both server and DNS name… it seems to be just the DesignerLauncher thus far that has issues.
I’m getting a related issue, so I figured I’d add it here (and to bump this topic since it’s unanswered) – I have Ignition running on a local VM, and I can connect to the web gateway using the server name, and it lets me add the application to the designer using the server name, but I get the same error when trying to launch the Designer (UnknownHostException: null). The only way I can launch the Designer is by using the IP address.
I think both of you are running into the same issue, which is that ultimately an underscore is not a legal character to appear in the hostname component of a URI/URL.
My guess is that when adding a gateway there must be a regex or some other superficial API that doesn’t do validation, but when it comes time to actually connect the validation occurs. Java is pretty strict about URI/URL following the spec.
To avoid heartache don’t assign hostnames with underscores if they’re ever going to appear in a URL.