For the password I have tried the Domain Update Key and the Account Update Key but both fail. For the login I am of the understanding that it can be anything as long as it’s not left .
If you have multiple sub-domains and you are not wildcarding then you can use a config as follows (Note: the :1 and :2: appended to provider default@ipv64.net)
innadyn v2.0 configuration file format
period = 1800 #verify-address = false
You can find the correct DynDNS update token in your domain overview.
Click on the domain name and display the security field.