Errors in currently selected datapacks prevented the world from loading. You can either try to load it with only the vanilla data pack ("safe mode"), or go back to the title screen and fix it manually.

[DevilAngel]

My Pc crashed and now im unable to connect to a world, what do i do?

I dont have Modpacks on it so it doesnt makes sense, and i dont want to load a backup cause i just farmed a lot of stuff for a farm and dont want to do it again!

[Bedrock]

Go to the logs-folder and add the latest.log from there