Debian :: Cron Task Not Working

I have a ts3.desktop file in my /usr/share/applications folder that I want to run on system boot. I have typed the following commands which don't work

Code: Select allcrontab -e

Then in the editor, I typed the following line at the bottom of file. I also made the necessary carriage return after this line.

Code: Select all@reboot gtk-launch ts3 /usr/share/applications

Then I pressed ctrl+o to save it.

After I put these commands in, I did the following command to troubleshooting this issue, see below.

Code: Select all$ crontab -l
no crontab for server
$ps -ef | grep cron | grep -v grep
root         532      1   0 21:35 ?                 00:00:00 /usr/sbin/cron -f

But after I reboot and nothing happens, the application doesn't start.