server not starting

I wanted to transfer my singleplayer survival world to an online server so my friends can play, I transferred the map files and did everything and it constantly starts getting stuck on stuff like "java.lang.Thread.run(Thread.java:748) [?:1.8.0_275]" and stuff like "generating world spawn: 87%" and then crashing after a while

Thanks for the reply but I managed to get it fixed thanks for willing to help