Ssh login fails for user@mydc.domain but works with just the user name

Moritz,

of course, you’re right. ssh work from an linux host with Administrator@mydc.domain.
The origin is an error when setting up an backup dc. During setup the server is unable to contact the primary dc indicating that the login via ssh fails to the primary dc. See image.
image
As this error occures at setup time I cannot check the join log…

Any idea?

Thank you for your help.

Greetings

Chris