Unfortunately the link to 3Dprint a spartan with Sandboxr is broken. anyone have any luck?
It’s a known issue that has been escalated to the appropriate team. They’ll likely look into it as soon as they can, hopefully soon now that the holidays are winding down 
For more info, you can follow https://www.halowaypoint.com/en-us/forums/8f4648981f554a9d86527a5754966e89/topics/3d-printed-spartan-page-won-t-load/ee606953-793d-4045-9bbe-2cfaeba98f17/posts