CalDAV Sync issues Fantastical / Airmail

CalDAV Sync issues Fantastical / Airmail

Hi there, Iam using Fantastical as my osx calendar program.
I am experiencing no sync here.

I have the error that pops up sometimes:
Fantastical encountered an error while communicating with the server.

Error: Request failed with status code 403.
https://calendar.zoho.com/caldav/8d57cac1999f4f2ae02f2d23968c5f10eaf15807850316d40c761d4fd553ff584a64100d17cdc3bb/events/

I also have an issue when I recieve a calendar invite that, when I click Yes to an invite, it never get´ synced to my calendar...

I have also added an screenshot for the fantastical setup.

Do you know what the issue can be?