I think I managed it now (sorry).
175219 : ************ ************** ************** **************
175219 note : PID '7015' started at 2025-02-28 17:52
175219 : ddns version : 2.8.2-43
175219 : uci configuration:
ddns.ip64.cacert='/etc/ssl/certs/ca-certificates.crt'
ddns.ip64.check_unit='minutes'
ddns.ip64.domain='lallkopf.lan64.de'
ddns.ip64.enabled='1'
ddns.ip64.force_unit='minutes'
ddns.ip64.interface='wan'
ddns.ip64.ip_network='wan'
ddns.ip64.ip_source='network'
ddns.ip64.lookup_host='lallkopf.lan64.de'
ddns.ip64.password='***PW***'
ddns.ip64.retry_unit='seconds'
ddns.ip64.update_url='http://ipv64.net/nic/update?domain=[DOMAIN]&key=[PASSWORD]
ddns.ip64.use_https='1'
ddns.ip64.use_ipv6='0'
ddns.ip64.use_syslog='2'
ddns.ip64.username='none'
ddns.ip64=service
175219 : verbose mode : 0 - run normal, NO console output
175219 : check interval: 600 seconds
175219 : force interval: 4320 seconds
175219 : retry interval: 60 seconds
175219 : retry max count : 0 times
175219 : No old process
175219 : last update: never
175219 : Detect registered/public IP
175219 : #> /usr/bin/khost -t A lallkopf.lan64.de >/var/run/ddns/ip64.da
175219 WARN : NO valid IP found
175219 info : Starting main loop at 2025-02-28 17:52
175219 : Detect current IP on 'network'
175219 ERROR : Can not detect current IP using network_get_ipaddr 'wan' - Error
175219 WARN : PID '7015' exit WITH ERROR '1' at 2025-02-28 17:52