@Dennis-010

Thanks for figuring all of this out. I also reverted back to the X11 window driver.
For completeness, just add --rotate right to the command:

customCommand: { // Optional, See "Using Custom Commands" below monitorOnCommand: 'xrandr -d :0 --output HDMI-1 --auto --rotate right', monitorOffCommand: 'xrandr -d :0 --output HDMI-1 --off' },

@Dennis-010 said in MMM-Calendar not seem to load .ics:

You are a genius!!

well, i don’t know about that… I’ve just spent the last few years fixing bugs in there

I think the problem was somewhere in my mailserver.
After a reboot all the appointments magicly reappeared.

Thank you for responding.