Please fill out the missing (relevant) fields, otherwise we cannot assist you with the problem you are experiencing.
Missing:
GTA V version?
Did you try to delete caches.xml and try again?
Error screenshot (if any)
What did you do to get this issue?
What server did you get this issue on?
CitizenFX.log file
.dmp files/report IDs
GTA V folder screenshot
GTA V/update/x64/dlcpacks screenshot
Filepath to FiveM folder
FiveM client folder screenshot
Did you try to disable/uninstall your Anti-virus?
Also add what you already tried so far.
Please fill out those fields, so we have enough information to go on!