WebDAV calendar updates fail

I have an issue where I can publish a calendar to a WebDAV server and the persons who are intended to be able to access it are able to, but when the Calendar changes and Outlook 2019 tries to update the published calendar on the WebDAV server, it fails.

I have provided a link below to a discussion thread I started on answers.microsoft.com, but they were of little help and after days of waiting I got nowhere other than I was told to open a trouble ticket with Microsoft Support, eventually I found my way to an Outlook support rep with Microsoft, who told me they couldn't help with my failing Outlook function (WebDAV publishing) and sent me here. Are you able to help??

Discussion thread that explains the issue in more detail:
https://answers.microsoft.com/en-us/outlook_com/forum/all/outlook-will-publish-but-not-update-a-calendar-on/34a9ebde-885e-488b-bb0b-1b356b90974b

I hope someone can help, the process to publish calendars to a WebDAV server are pretty straightforward, yet the process is failing.