Over the weekend it seems that the support for deeplinks has been broken; our client reached out to us to state that they got a Roblox 404 error with links that worked just fine on the 31th of September.
Can you verify what platforms this issue occurs on? There’s a known issue where URL encoded double-quotes are stripped out on Windows: Deeplinking corrupts JSON data - #4 by FourPointFourly, but trying out some test links on iOS and Android, I’m still seeing both work on my side.
Wait, are these being typed(or pasted) directly into the browser URL bar on Windows/macOS? If so, and the user isn’t logged in, there’s a known issue where it brings the user to a 404 page.