There should be a folder inside your core folder named
Crashes or maybe lowercase on a Linux server (I currently don't have access to a Linux environment). You should be able to find one or more crash logs there. It is recommended that you copy the content from the most recent crash log and post it, either as a link to a gist file on your github account or as a MarkDown block in the issue post (use back ticks ``` before and after the log text block to preserve the text layout).
on linux you need to run it under gdb
gdb -x crashreport.gdb path_to_worldserver,
crashreport.gdb file can be found here https://github.com/TrinityCore/TrinityCore/tree/3.3.5/contrib/debugger