Printing from Ubuntu 20.04 did no work over UCS Cups - Job held for authentication

Hello all,

i binded here an fresh Ubuntu Installation to UCS. Domainbind was done with the UCS JOIN Programm from Github. Everything works fine. But print pages with all printers the are installed on ucs did not work. The error message in Ubuntu’s local cups is:

E [01/Aug/2020:14:33:05 +0200] [Job 9] Job held for authentication.

On 18.04 we did not have this problem. Kerberos on 20.04 works fine. And on UCS is no rule. It is the default:
Allow access for all users / groups.
I found this: UCS CUPS Print Server - Hold For Authentication
No other way, strange.

What are the requirements to be able to print normally on Ubuntu clients?

My local CUPS has the default Sambaline for adding printers:
smb://dc1.tux.lan/00-printblack-Schwarz-Laser

I have also set this:
ucr set cups/automaticrestrict=no