Brocade FC switch: Unable to collect ConfigUpload or Supportsave via SCP and SFTP (scp failed)

 Situation:

• host with OS Linux (RHEL, Rocky Linux etc.)
• host can access to switch
• no firewall blocks between switch and host
• network admin open access from switch to host on 22 port
• but configUpload returns error: scp failed

 SCP Example:
switch:admin> configupload
Protocol (scp, ftp, sftp, local) [ftp]: scp
Do you want to continue with CRA (Y/N) [N]: y
Server Name or IP Address [host]: 10.0.0.1
User Name [user]: admin
Path/Filename [<home dir>/config.txt]: /configupload.scp
Section (all|chassis|switch [all]): switch
lost connection
configUpload not permitted (scp failed).
Terminated

 Resolution:

Clear all known hosts keys on switch:
sshutil delknownhost -all

Found this on Dell support knowledge base:
Connectrix B-Series:Unable to collect ConfigUpload or Supportsave via SCP and SFTP