The Roblox error 500 can be one of the indicators of an on-going server problem so what you have to do is to check the game’s server status.

Anytime you see the “HTTP 500: “Internal Server Error” message in Roblox, you’re either trying to publish your game or make changes to it on the backend.

Online game platform Roblox is reportedly experiencing widespread issues in the US, with users encountering an "internal server error." At 5:45 p.m. EDT, Downdetector recorded over 35,000 reports of ...

The Roblox error starting experience occurs due to not using proper DNS settings or not running the Roblox as an administrator. In this case, you can try using the Google DNS.