Please Report Me! I Have This Problem A Month!
21.08 03:47:02 [Server] INFO Disabling Multiverse-Core v2.5-b641
21.08 03:47:00 [Server] INFO java.lang.OutOfMemoryError: Java heap space
21.08 03:47:00 [Server] SEVERE Error occurred (in the plugin loader) while cancelling tasks for EssentialsAntiBuild vPre2.12.1.2 (Is it up to date?)
21.08 03:46:55 [Server] INFO Disabling EssentialsAntiBuild vPre2.12.1.2
21.08 03:46:50 [Server] INFO java.lang.OutOfMemoryError: Java heap space
21.08 03:46:50 [Server] SEVERE Error occurred (in the plugin loader) while cancelling tasks for Multiverse-Portals v2.4-b548 (Is it up to date?)
21.08 03:46:46 [Server] INFO Disabling Multiverse-Portals v2.4-b548
21.08 03:46:44 [Server] INFO Stopping server
21.08 03:46:42 [Server] INFO java.lang.OutOfMemoryError: Java heap space
21.08 03:46:42 [Server] SEVERE Encountered an unexpected exception OutOfMemoryError
21.08 03:46:41 [Server] SEVERE java.lang.OutOfMemoryError: Java heap space
21.08 03:37:44 [Server] INFO - Version 2.4-b548 Enabled - By Rigby and fernferret
21.08 03:37:44 [Server] INFO Enabling Multiverse-Portals v2.4-b548

You dont have enough RAM

"Java heap space" means java/ram is full -> cant load files etc -> crash -> server stop