To get your HP printer back online, you can try the following effective steps:

1. **Check the printer connection**
– For USB printers: Ensure the cable is securely plugged into both printer and computer.
– For wireless printers: Verify the printer is connected to the correct Wi-Fi network and the wireless light is solid, not blinking or off.
– For Ethernet connections: Check the cable for damage and reconnect to a different router port if necessary[1][2].

2. **Restart your devices**
– Turn off and unplug your printer.
– Restart your computer and router.
– Plug in and turn on your printer, then try printing again[1][2][3].

3. **Disable “Use Printer Offline” mode**
– On Windows, go to Control Panel > Devices and Printers.
– Right-click your HP printer and if “Use Printer Offline” is checked, uncheck it to bring the printer back online[1][2].

4. **Set your printer as the default**
– In Control Panel > Devices and Printers, right-click your HP printer and select “Set as Default Printer” (or in Windows 10/11, Settings > Devices > Printers & Scanners, uncheck “Let Windows manage my default printer” and manually set it)[1][4].

5. **Clear any stuck print jobs**
– Right-click your printer in Devices and Printers and select “See what’s printing.” Cancel any pending print jobs to avoid blockage[1].

6. **Use HP troubleshooting tools**
– Download and run the HP Print and Scan Doctor application to automatically diagnose and fix printing issues.
– Alternatively, use the Diagnose & Fix tool in the HP Smart desktop app for assistance[4].

If these steps don’t resolve the issue, consider:
– Checking for driver updates or reinstalling the printer driver.
– Temporarily disabling firewall or antivirus that might block printer communication.
– Resetting your printer’s network settings and reconnecting it to Wi-Fi using the HP wireless setup wizard or HP Smart app[4].

These steps cover the most common causes and solutions for an HP printer being offline[1][2][4].