VPN SSL connection from outside

Hello,

I'm a newby and I configure the first firewall, a Sophos XG115 firewall.

There was a RaspberryPi with OpenVPN before the firewall installation to reach the internal ressources from outside.

Now, this should be able with the XG. I've tried a few things with a few instructions, but nothing worked.

I have a DynDNS account (like before with the RaspberryPi)...

I tried this: https://community.sophos.com/kb/en-us/122769 but without the subnet, because I want to reach a specific virtual machine on a server.

In the VPN Settings, I've tried to fill the Overrite Hostname with the url from the DynDNS. This Url shows the correct external IP in the SSL VPN Client from external.

 

But there is a TSL error in the log and I cannot create a VPN connection.

Is there anything wrong in the firewall rules?

 

Thanks.