auth

I use the Dude 3.6 with a handful of mikrotiks mostly RB750 and RB951-2n.
With one Rb750 wich runs ROS 6.6 i have the problem that unter Devices->RouterOS Status is auth failed although i have entered the correct
password and i can log in to winbox via rightclick → Tools → Winbox.
The problem is that i cant update it that way via the dude.
Is there any setting i need to activate on the rb750?

ip service print gives:

admin@MikroTik] /ip service> print
Flags: X - disabled, I - invalid 
 #   NAME      PORT ADDRESS                                       CERTIFICATE  
 0   telnet      23
 1   ftp         21
 2   www         80
 3   ssh         22
 4   www-ssl    443                                               none         
 5   api       8728
 6   winbox    8291
 7   api-ssl   8729

Thanks for any advice