Encountering an error on Roblox is the worst, especially if it happens out of nowhere. In some cases (the best cases), these errors can be fixed by simply resetting your internet or deleting and redownloading the Roblox app, but in other cases, the problem is a bit more complex and may require assistance from Roblox itself.

Normally this "error" appears when a server you are trying to connect to on Roblox is full. I use the term error loosely, because there is nothing wrong with Roblox when this screen appears, so there is no error to fix. You should simply try connecting to a different server.

If that doesn't work, I would try closing Roblox and leaving it for a while, and also resetting your internet, and then trying Roblox again. Clearing your device's cache and turning it off and on again wouldn't hurt either; if that doesn't work, I would suggest contacting support as soon as possible and explaining your situation.

Almost 100% of the time when you play Roblox, you will load into an experience almost instantly without any issues. This is because Roblox purposefully places you on servers that have open slots, meaning they are not full, or nearly full, of other players. That way, you never have to worry about getting kicked out of a loading process just because someone else halfway around the world is trying to join the same experience as you at the exact same time.