Accessing my caldav with ddns Zywall 110

Figge71

Hi! I'm having som trubbel accessing my caldav calendar when using it within the network wiht ddns, it works fine when useing 4g and it works fine when accecing it within the network when using the ip address.

Can anyone help me with whati'm doing wrong?

Zywall 110
Latest firmware

jasailafan

Could you describe the way you access caldav? Is it a caldav server in lan and you'd like to access it through NAT from wan(DDNS)?