After some downtime due to technical issues, the build server has been reopened now.
For more information: https://simplicitypvp.net/w/Build_server
The same rules as before apply to the build server.
It's not hosted on the same hardware as the main server. For this reason, it's accessed using a SRV record. There are reports of some users (apparently all on Mac) having difficulty connecting to the server. If you get an error connecting to build.simpvp.net (other than not being whitelisted) ask an admin for help.