cups problem version >= cups-2.4.7-1.2ubuntu7.9

[michaelkohls]

There is a problem with cups versions >= cups-2.4.7-1.2ubuntu7.9 using cupsd.conf template.
Simple adding a "@Printing" in file "cupsd.conf", line 52 solves the problem.
See also: https://ask.linuxmuster.net/t/nach-server-update-kann-nicht-mehr-gedruckt-werden/12193/9

[HappyBasher]

Note: On a multischool environment there should also be a entry like @<schoolname>-printing.