ddclient - Could not connect to dynv6.com

I use dynv6.com as a DynDNS Service for me an my customers. During the last installation of the service at a client, I ran into a issue with ddclient not sending the update to dynv6.com.

root@zoidberg:~# ddclient --force
FAILED:   updating zoidberg.ddns.level66.network: Could not connect to dynv6.com.

I used the configuration values from the dynv6.com site but it seems they did not be enough.

root@gw:~# cat /etc/ddclient.conf 
# Configuration file for ddclient generated by debconf
#
# /etc/ddclient.conf
protocol=dyndns2
use=if, if=eth0
server=dynv6.com
login=none
password=asdasdasdiiugofiugoisfugj
zoidberg.ddns.level66.network

root@gw:~# ddclient -debug --force
DEBUG:    Reply from 'ip -4 -o addr show dev wwan0 scope global' :
DEBUG:    ------
DEBUG:    6: eth0    inet 37.80.164.188/29 scope global wwan0\       valid_lft forever preferred_lft forever
DEBUG:    ------
DEBUG:    get_ip: using if, eth0 reports 37.80.164.188
DEBUG:    
DEBUG:    nic_dyndns2_update -------------------
DEBUG:    proxy    = <undefined>
DEBUG:    protocol = http
DEBUG:    server   = dynv6.com
DEBUG:    url      = nic/update?<redacted>
DEBUG:    ip ver   = 
FAILED:   updating zoidberg.ddns.level66.network: Could not connect to dynv6.com.

After some digging into the debug output of ddclient, I enabled SSL/TLS in the update method and it seems to do the trick.

root@gw:~# cat /etc/ddclient.conf 
# Configuration file for ddclient generated by debconf
#
# /etc/ddclient.conf
protocol=dyndns2
use=if, if=eth0
server=dynv6.com
ssl=yes
login=none
password=asdasdasdiiugofiugoisfugj
zoidberg.ddns.level66.network