Thank you for your replies!
That’s not the issue I guess…
I have entered the 257 KSK key already in the webinterface of do.de , however there is that error message.
It is a bit strange since the 256 CSK key from 1984.hosting was working fine on do.de… However, 1984.hosting doesn’t offer the options I need, whereas desec.io does!
But there is no way to enter a DS key on do.de …
Thanks for reproducing my issue! Very strange that the NAST check works on your domain, but not on mine…!
I will write to the do.de support and ask them to assist me …