Hello everyone,

I currently have 3 DynDNS entries set up through Dynu. Now I would like all 3 to get the same IP, but I can only make one DynDNS entry in the Fritzbox.

Domain: Group:
test1.dynuddns.com TestDynGrp
test2.dynuddns.com TestDynGrp
test3.dynuddns.com TestDynGrp

Update URL: http://api.dynu.com/nic/update?hostname=[HOSTNAME]&myip=[IP ADDRESS]&myipv6=[IPv6 ADDRESS]&password=[PASSWORD]
Domain Name: dynuddns.com
User in the Fritzbox is: TestDynGrp
Password in the Fritzbox: xyz123123testExample

What am I doing wrong?

I would say use groups, but I've found with my Synology NAS that the group update doesn't seem to work. So I'm in a similar situation as you. 3 hostnames and only one can be set on my NAS.

Remove all hostnames out of group if they are assigned to one. In the router DDNS settings, use an invalid domain name such as test1 instead of test1.dynuddns.com.