Server keeps crashing

[OofyMcBoofy]

Hi 

I just wanted to know what's going on in my server. Basically, yesterday I put the randomtickspeed to 1000 to try and make some leaves despawn quicker and nothing happened. Then, the server shut down and now whenever I start it up and join it I either can't join or I can and whenever I do any command (like /dl to try and get a .zip file of the world so I could reset the server and add that file to get everything back) the server just shuts down again and it says something like "Can not connect you to a default or fallback server"

Any help would be appreciated as me and my friends spent a lot of time on this server and would hate to see it all go to waste.

(Edit: Ok I just remembered that I saved a copy of the world before someone joined it so do you know how I can get that copy there instead of the one now as that would be great)

Edited October 19, 2020 by OofyMcBoofy