apt-mirror is already running, exiting at /usr/bin/apt-mirror line 187.
This happens when you have an error in one of the lines in mirror.list apt-mirror crashes without clearing it’s lock file. It will need to be cleared manually before apt-mirror will run. My mirror, is in the directory
Therefore, to remove the lock open a terminal and:
sudo rm /home/debian/spool/apt-mirror/var/apt-mirror.lock
At that point apt-mirror should run normally.