Funktioniert das auch nicht, wenn du den cronjob über Arkmanager anlegst?
hier der Auszug aus der Dokumentation dazu:
install-cronjob <command>
Installs a cron job that executes the specified command.
This accepts any of the options the specified command accepts,
as well as the following options. In order to specify an
argument to the command (e.g. to the broadcast
command),
use the --arg=<arg>
option.
Please read your man 5 crontab
manpage to determine what
minute and hour values are valid, as some implementations
may not accept e.g. the */n
minute / hour specification.
--daily
The command should be executed daily
--hourly
The command should be executed hourly
--hour=<hour>
Specifies one or more hours when the command should execute. This is the hour field of the cron job.
If you want to have the command execute every n hours, then
use --hour='/n'
Default: (i.e. all hours)
--minute=<minute>
Specifies one or more minutes of the hour when the command should execute. This is the minute field of the cron job.
If you want to have the command execute every n minutes,
then use --minute='*/n'
Default: 0
(i.e. the first minute of the hour)
--enable-output
Enables the output from the command - the cron daemon usually
emails this to the user specified in the cron configuration
--arg=<arg>
Specifies an argument to pass to the command