Printing from LrC 11.5 MacOS 10.15.7, Canon Pro1

I have found recently that I cannot print from LrC 11.5 or Photoshop 23.5.1 When I try to print the print queue shows a Print Job in state "Printing" and the Data light on the printer flashes, but the printing does not start. I would normally expect to hear the printer clearning the inkjets before the printing begins, but even this does not happen

When I print the same file from an alternative photo processing application, it prints as expected.