Our OS images are pulled from specific SolusVM and non-SolusVM links/servers, and if those are down at any given moment, there's a fair possibility that they may fail, although rare.
In those cases, simply a question of trying later. Debian/Ubuntu images are directly pulled from Solus's own servers, for example.
You still have the possibility of using your own ISO image with cloud-init packages preinstalled, via our Portal.