Upstream work which might help, although it's about using the smbspool krb5 wrapper, it also has changes to the smbspool binary:
https://gitlab.com/samba-team/samba/merge_requests/961 ** Summary changed: - error when connecting to smb server + smb printing fails -- You received this bug notification because you are a member of Ubuntu Server, which is subscribed to samba in Ubuntu. https://bugs.launchpad.net/bugs/1849859 Title: smb printing fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cups/+bug/1849859/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs