Remix 3D and Paint 3D were both the highlight of the Windows 10 Creators Update, but it looks as though the features might not be as popular as Microsoft thinks. Noted by Thurrott.com, Remix3D.com is apparently being impeded by many ad-blocking extensions, giving users the appearance that the website has gone down.
It is not clear when ad blockers first started disabling access to Remix3D.com, but the post notes that it has been occurring since late Thursday evening. That timeframe is likely in which Remix3D.com was somehow added to a universal ad block list, but we can't confirm that for ourselves.
We tried things out on Chrome with UBlock origin and Remix3D.com loaded fine, but with uBlock origin in Microsoft Edge, the website was blocked and would not load. Disabling the ad blocker in Edge, however, would make the Remix3D.com website load up like usual.
It's very weird to see that Remix3D.com would be blocked by these extensions, and there's no clear reason as to why it happened in the first place. At any rate, even Microsoft looks to be distancing itself from Remix3D, as a recent version 5.1808.8017.0 update to Paint 3D buries the service from the main menu to a new "3D library" button in the UI.