I have removed the new SSH version and replaced it again with the old version. Some of the problems are fixed. SSH is possible again, but not for the root user. Telnet also works but again, not for the root user.

When trying a SSH connection as root the following error occures:
Authentication successful.
Received signal 11. (no core)

After this error the connection failes again. Does anyone has an idea of what this problem might be?

Thanks.