Does It Matter What USB Slot Your Printer Is In?
When a USB device is plugged into your computer or installed for use, the specific USB port that you've chosen to use generally doesn't affect how the device works. Your computer will recognize devices regardless of where you plug them in, though there are some limitations. If you have too many devices plugged in already, your computer may not have room to recognize it. You may also need to plug your printer in directly instead of through a port on a different device.
Your USB ports are connected to a USB hub that manages all the devices you have connected. These hubs have limited bandwidth, which will limit how many devices can be plugged in at a time. This may be why your printer will work while connected to one port, but not another. Some printers may also require a powered USB connection; indirect connections like USB hubs or keyboard USB ports are often not powered, so connect your printer directly to a port on your computer if it's not being recognized elsewhere.
If your printer normally works on one port but suddenly stops working, try restarting your computer or unplugging a few other USB devices, especially if you have a large number of devices plugged in. You can also try plugging your printer into a USB port on a different part of your computer. Finally, make sure that your USB cable is plugged in correctly to both your computer and printer, and that your printer’s drivers and software are installed.