My modded Forge 1.12 Minecraft server keeps crashing after running for several minutes with players on, and I'm not sure why this is happening. It was working fine all this morning, up until an hour ago when suddenly it crashed without warning. I restarted the server, and it ran for a few more minutes. Then it crashed again. I restarted my computer hoping it was maybe an OS issue, but the crashes kept coming minutes after the server would go up. I have no clue why this is happening.
your server is crashing due to high lag your need to edit your server startup script to allow java you use3e more then the stock ram about 4-5Gb ram would be a good start also make sure you match your hardware as well as your server. We can't tell you what args to use as every set up is different hence why you need to enter them yourself but there is plenty of resources out there a google of "minecraft modded java arguments" will give plenty of examples and walkthroughs.
It is the same args that you enter in your minecraft client so they should not be too confusing
Hmm seems there are no tutorials I can find on how to add java arguments in to the forge .jar server launcher. How do I do it? I'm very new to using mods on Minecraft and when it comes to launcher arguments, i'm afraid I have no idea what i'm doing.