Problem with first-time AddOn configuration DuckDNS

I’m new to this forum and I’m hoping for some help:
I just installed HA on a Raspi 3, created a domain with DuckDNS without any problems and now have the problem of entering this domain in the add-on for DuckDNS. Despite multiple attempts (also new installation), my domain entry disappears from the form and I cannot save the config.
Does anyone know this problem?

hey @zefra i have the same Problem. Did you solved it?