Not syncing calendars and throws errors

This plugin used to be working fine.
But I recently noticed that it displays unavailable dates as available.
I tried to sync the calendar and I got to WordPress critical error page.
The error i get is

An error of type E_ERROR was caused in line 2648 of the file /home/xxxxx/xxxxxxxx.xxxxxxx.gr/wp-content/plugins/vr-calendar-sync/Includes/Vendor/ics-parser/src/ICal/ICal.php. Error message: Uncaught Exception: The file path or URL ‘https://www.airbnb.gr/calendar/ical/156xxxx292917034406.ics?s=e848b7b79671729876562d8b640fa3f2’ does not exist. in /home/xxxxx/xxxxxxxx.xxxxxxx.gr/wp-content/plugins/vr-calendar-sync/Includes/Vendor/ics-parser/src/ICal/ICal.php:2648

The last sync was on December 18

Any help with this?

The page I need help with: [log in to see the link]