After working perfectly for a long time, my printer on my COSMIC Atomic laptop stopped working. After deleting and reinstalling the printer, I keep getting a message in the properties dialogue box that says “Credentials are invalid.” Which credentials? The printer is logged into WiFi and works fine with a macOS device. Anyone have any idea what’s wrong?
Other Fedora users also find this difficult to troubleshoot. See https://github.com/OpenPrinting/cups/issues/1046 for one “fix”.i
No help, unfortunately. There is nothing in /etc/cups/ssl.
‘ipps’ needs credentials, so they but they may have been lost or were stored elsewhere, usually under /etc or a user’s home directory.
With my HP Laserjet printer I find it works perfectly when using the hplip tools to configure it. I find there are often problems when using ipps or allowing avahi to automatically configure it.
Have you tried using hplip instead of ipps for configuring and printing?
Fedora does include hplip in the default installation (at least on the Workstation edition). Hplip does not require the credentials that seem to be your issue.