My crontab doesn't seem to be executing any commands

I have been having troubles setting up an auto reboot for my mc server.

My .sh file I have made works perfectly whenever I execute it, but when it comes to using crontab it seems to just do nothing (excluding one time), I have tried restarting & reinstalling it... it is safe to say I am out of my element as I am completely new to all of this.

The crontab line is this

0 20 * * * /VHServer/reboot.sh

nothing has changed since I made that line of code, it worked the first time and then never again.

The .sh file looks like this and it runs perfectly with a manual command.

echo "Server reboot STARTED"

# Letting people know that the server is going to restart
tmux send-keys -t VHS "/say §c Server restarting in §r§6§l30 minutes. §r§cPleas>

# Wait for 1770 seconds (25 minutes)
sleep 1500s

# Send messages to the server indicating the restart countdown
tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l5 minutes! §r§cThe>
sleep 270s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l30 seconds! §r§cTh>
sleep 20s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l10 seconds!" Enter
sleep 5s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l5 seconds!" Enter
sleep 1s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l4 seconds!" Enter
sleep 1s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l3 seconds!" Enter
sleep 1s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l2 seconds!" Enter
sleep 1s

tmux send-keys -t VHS "/say §c Server is restarting in §r§6§l1 second!" Enter
sleep 1s

# Stop the Minecraft server
tmux send-keys -t VHS "/stop" Enter
sleep 60s

# Detatch from the tmux session
tmux send-keys VHS C-b d
sleep 15s

# Check if the session exists and kills session
if tmux has-session -t VHS> /dev/null; then
    echo "Killing tmux session 'VHS'."
    tmux kill-session -t VHS
else
    echo "Tmux session 'VHS' does not exist."
fi
sleep 15s

# Check if a session with the same name already exists
if tmux has-session -t VHS> /dev/null; then
    echo "Tmux session 'VHS' already exists. Attaching to it."
    tmux attach-session -t VHS
else
    echo "Creating new tmux session 'VHS'."
    tmux new-session -s VHS
fi
sleep 30s

# Restart the server using the run.sh script
tmux send-keys -t VHS "/home/ubuntu/VHServer/run.sh" Enter

echo "Server Rebooting"
sleep 60s

echo  "reboot COMPLETE"

I have had suggestions to run the crontab using sudo and also adding either sudo or the username "ubuntu" to the line of code within it, I have tried and there has been no output whatsoever.

I ran:

tail -f /var/log/syslog

and this only came back with the edits of the crontab, not once did the cron execute any command.

I hope this is enough information to provide a fix, I am at a complete loss and still learning about all of this, so I am sure I am not understanding something within all of this.

Your script should begin with:

#!/bin/bash

Replace tmux with the absolute path (type -p tmux). cron jobs have a different runtime environment, different $PATH, no $DISPLAY, etc. Read man -a crontab.