I am using the latest version of Firefox (84.0.1) on an HP desktop using Windows 7 Professional. The printer has been working fine until just recently. The problem might have begun when I updated Firefox recently, but I am not sure if this is true. After turning on the desktop, the first time I try to print something using Firefox the printer (Brother HL-5370DW) starts to print but then doesn't actually print anything. The thing I am trying to print shows up in the printer queue, but does not print, and then eventually appears in the queue as an error. After I run the Windows 7 troubleshooter, the printer will then print from that point on until I turn the desktop off again. If I try to print something twice unsuccessfully, and then run the troubleshooter, I will get two copies of whatever I was trying to print, even if I deleted the first copy in the printer queue. I am not sure if this problem is related to Firefox, but as far as I'm aware I haven't changed anything else on my system lately besides updating the Firefox version. Thanks.