Hello everybody.
Looks like internet printing configured via IPP over HTTPS is broken after 2.2.5.

We tried with the latest CUPS 2.2.9 on MACOS Mojave version 10.14.3 and with other intermediate versions on different Linux Distro, but the result is always the same.. the print job remains in the local queue and never get submitted to the server.

This is what we get on the IIS log on the print server:
2019-02-11 15:25:00 10.4.1.61 POST /printers/Stampante1/.printer - 443 - 10.4.66.16 CUPS/2.2.9+(Darwin+18.2.0;+x86_64)+IPP/2.0 - 401 2 5 0
2019-02-11 15:25:11 10.4.1.61 POST /printers/Stampante1/.printer - 443 - 10.4.66.16 CUPS/2.2.9+(Darwin+18.2.0;+x86_64)+IPP/2.0 - 401 2 5 0
2019-02-11 15:25:54 10.4.1.61 POST /printers/Stampante1/.printer - 443 - 10.4.66.16 CUPS/2.2.9+(Darwin+18.2.0;+x86_64)+IPP/2.0 - 401 2 5 0
NO username and error Access Denied returned..

When using the version 2.2.5, on the IIS server we can see the user name correctly and no errors:
2019-02-11 14:39:48 10.4.1.61 POST /printers/Stampante1/.printer - 443 Domain\username 10.4.66.53 CUPS/2.2.5+(Darwin+17.7.0;+x86_64)+IPP/2.0 - 200 0 0 15
2019-02-11 14:39:48 10.4.1.61 POST /printers/Stampante1/.printer - 443 Domain\username 10.4.66.53 CUPS/2.2.5+(Darwin+17.7.0;+x86_64)+IPP/2.0 - 200 0 0 0
2019-02-11 14:39:50 10.4.1.61 POST /printers/Stampante1/.printer - 443 Domain\username 10.4.66.53 CUPS/2.2.5+(Darwin+17.7.0;+x86_64)+IPP/2.0 - 200 0 0 15
2019-02-11 14:39:50 10.4.1.61 POST /printers/Stampante1/.printer - 443 Domain\username 10.4.66.53 CUPS/2.2.5+(Darwin+17.7.0;+x86_64)+IPP/2.0 - 200 0 0 0
2019-02-11 14:39:50 10.4.1.61 POST /printers/Stampante1/.printer - 443 Domain\username 10.4.66.53 CUPS/2.2.5+(Darwin+17.7.0;+x86_64)+IPP/2.0 - 200 0 0 1051
2019-02-11 14:39:50 10.4.1.61 POST /printers/Stampante1/.printer - 443 Domain\username 10.4.66.53 CUPS/2.2.5+(Darwin+17.7.0;+x86_64)+IPP/2.0 - 200 0 0 15

Is this a known problem? is there anything new to configure in the CUPS to make this work as before?

Thanks!
-mario