Grubsi

But you convinced the support that there might be something going on on their side 😊

Yes it's working for me! Thanks!

I guess they have updated or changed something and now the web server returns 308 on the URL with the slash at the end. Most clients won't have a problem as they follow the redirect.

I have not tested creating new or updating entries before. I looked into creating and updating now. Updating seems to work. Creating fails with 404, because of how the URL is generated here: https://sourceforge.net/p/outlookcaldavsynchronizer/code/ci/master/tree/CalDavSynchronizer/DataAccess/CardDavDataAccess.cs#l245 The .Net new Uri replaces the Contact part at the end with the name of the VCard. So we will have to wait for a new version or a fix at GMX and WEB.DE.

The problem is a redirect to URLs without a slash at the end. As a workaround for my GMX sync I did the following: Open the CalDav folder in your AppData: %appdata%..\Local\CalDavSynchronizer\ In the profiles.xml you find the GUID of the correct profile. Open the folder with that GUID. There open the options.xml and remove the final slash in the CalenderUrl tag.

The problem is a redirect to URLs without a slash at the end. As a workaround I did the following: Open the CalDav folder in your AppData: %appdata%..\Local\CalDavSynchronizer\ In the profiles.xml you find the GUID of the correct profile. Open the folder with that GUID. There open the options.xml and remove the final slash in the CalenderUrl tag.