Hi guys,
I implemented a workaround for this, which I wanted to share (just in case someone else faces the same problems).

I tried almost everything to get this thing running with the link (the direct link to the calendar didn’t work, but if I put the .ics file to a readable directory everything is fine).

The interesting thing is; even if I CURL’ that Nextcloud/Owncloud link, it shows me a well-formed calendar structure (so I can safely say that it hasn’t to do anything with user/pass combination, nor the fact that I’m using TFA (that’s why Nextcloud/Owncloud is providing app-PINs).

So, to get that thing working (as mentioned earlier by using a workaround), you need 2 things; a shell-script and a cronjob.

A shell-script downloads the .ics given by the export-URL of Nextcloud/Owncloud and stores it in a directory which has to be accessible by your MM distribution.

The timestamp variable inherits the current UNIX timestamp in order to only retrieve calendar entries that are (right now or) in the future to keep the file-size small and MM’s calendar-fetcher performant. Please note that –http-user is defined without [ " ] and –http-password is defined with [ " ] - that’s no typo! If you’re using self-signed certificates, ensure that you’re using –no-check-certificate in order to avoid issues with certificate validation by WGET module.

SSH’ in and type cd /usr/local/bin create a new shell-script with your desired editor by nano YOUR_SHELLSCRIPT_NAME.sh save that file after putting below code into it make it executable with chmod +x YOUR_SHELLSCRIPT_NAME.sh if you like, give it a first try :) #!/bin/bash timestamp=$(date +%s) wget --no-check-certificate --output-document="YOUR_READABLE_DIRECTORY/YOUR_DESIRED_FILENAME.ics" --auth-no-challenge --http-user=YOUR_NEXTCLOUD_USER --http-password="YOUR_APP_PIN" "https://YOUR_NEXTCLOUD_IP/remote.php/dav/calendars/YOUR_NEXTCLOUD_USER/YOUR_NEXTCLOUDCALENDAR_NAME?export&start=$timestamp&componentType=VEVENT" I decided to run that shell-script every 30 minutes so my MM calendar display is updated twice per hour.

To do so, type crontab -e, add the following at the bottom and save;

# NEXTCLOUD Calendar Export 0,30 * * * * /usr/local/bin/YOUR_SHELLSCRIPT_NAME.sh

Of course you can use any cron you like!