root's crontab wants to send to FQDN email instead of just jim

I'm using (as I have been for decades) calendar, called from root's crontab at 0200 every morning. Problem is, it's running, but the emails go to root's email as bounced messages.

Seems root is trying to send to jim@JinxsSlack.local, which is the system name. root's line in crontab reads:

0 2 * * /usr/bin/calendar -a

Is there a specific way in calendar (running from root's crontab) that I can tell it to use jim, not jim@...... ? Or perhaps as an option in crontab? The man page for crontab is for the command only. There is no crontab(5) for the crontab file, itself (nor is there one in any other man sections---I did a "ls crontab **/*" and the only place it was found was crontab(1).

Looks like I need to copy yet another file from my old Mint system. Hell, I had to copy all of the calendar stuff from there because slackware couldn't fine it---no idea where it is on slackware or why it isn't in a "normal" path (nor are the man pages for it).

So does anyone know how to make calendar's entry in root's crontab send to me as jim only, as again, opposed to jim@blaBlahBlah?

Thanks,
--jim