CalDav Account won't connect

[PMG-Me]

Hi,

I've been trying to sync up my caldav account to my native apple calendar app but it wont connect.
I have tried using the configuration file that is sent by webmail, but also setting it up manually by using the server address and port number.

Neither worked.

Could anybody give specific guidance? The devices I'm setting up on is a MacbookPro 2023


Thanks in advance