Just a quick update that we have resolved this issue with our recent hotfix.
Thanks for your patience!
You may be aware that we are currently experiencing an issue which prevents Solo and Corrupted Dungeons from spawning as frequently (see Call to Arms – Known Issues).
We’ve found that this issue appears to be affecting Hellgates as well.
As a temporary workaround, you can try heading over to more remote places, such as those in the Outlands and away from the Portal regions to find available Hellgates and Dungeons.
Our devs are working on a fix urgently and we hope to have this over to you as soon as possible! We will give you a status update within the next few hours.
– Mytherceria & Dev Team