Why can i not print to a network attached printer from Ubuntu?

I am using my Rasberry Pi as a print server using Samba. I have followed this tutorial, but i cannot print from my ubuntu laptop. I have added it as Windows Printer via Samba. But i get the NT_STATUS_ACCESS_DENIED error when i try to print. If i add credentials when i add the printer (i use my raspberry pi username and password (which should be added to the right group)) i get: "Not authorized, The password may be incorrect."

I know i could just as well post this in a raspberry pi forum, but since the problem is only with Linux/Ubuntu i thought i would post it here...