Running FireFox 77.0.1 and trying to drive an HP Envy 6255 (wireless) printer. All other programs (including Thunderbird, Adobe Reader, Microsoft Edge etc) print without problems. I have worked through each and every step of the Printing Troubleshooting steps, including refreshing and reinstallation of FireFox, without success. The only add on I am using is DuckDuckGo, and I even tried printing without it.

Everything was running fine until a few days ago. (Windows 10 updates have not been added, and even if they had slipped through, everything else is still working as of this morning.) It still works off my iOS devices. The networks have not changed. Any ideas?