upload file to mikrotik router

I try to upload created certificate to mikrotik from Ubuntu system for SSTP connection with Windows client as

mikrotikuser@MikroTik] /tool> fetch address=123.456.789.101 src-path=/home/certificate/server.crt user=ubuntuuser mode=ftp password=syspassword dst-path=server.crt port=21 host="" keep-result=yes

I get error:

  status: failed
failure: connection failed