JSON message not found

Hello,
I’m using Debian 10 with ddclient. I set up a new server and I like to update my up via dynv6
I also used it on my old server with the same configuration.

root@server:/home/admini# cat /etc/ddclient.conf

Configuration file for ddclient generated by debconf

/etc/ddclient.conf

protocol=dyndns2
use=web
server=dynv6-com/api/update (replace - with .)
login=xyz
password=none
xyz-dynv6-com (replace - with .)
root@server:/home/admini#

When I try to manually update
#only necessary output
UPDATE: updating removed
CONNECT: (dynv6-com, relpace - through .)
CONNECTED: using HTTP
SENDING: GET /api/update/nic/update?system=dyndns&hostname=xyz.dynv6.net&myip=1.2.3.4 HTTP/1.0
SENDING: Host: dynv6-com (replace - with .)
SENDING: Authorization: Basic password(from Instructions)=
SENDING: User-Agent: ddclient/3.8.3
SENDING: Connection: close
SENDING:
RECEIVE: HTTP/1.0 404 Not Found
RECEIVE: Access-Control-Allow-Origin:
RECEIVE: Content-Length: 24
RECEIVE: Content-Type: application/json; charset=UTF-8
RECEIVE: Date: Sat, 26 Sep 2020 12:15:33 GMT
RECEIVE: Server: Caddy
RECEIVE: Vary: Origin
RECEIVE:
RECEIVE: {“message”:“Not Found”}
root@server:/home/admini#
The IP detection works properly. If I try to open the URL in the browser, I do not have to enter any credentials.
It returns a JSON-message with the content Not found.
{“message”:“Not Found”}
Is my configuration bad or is it a fault at dynv6?

PS: Only 2 links allowed is really annoying.
Kind regards