The panel already told you what's wrong. We translate it.

Why it happens

Windows marks a printer offline when it stops getting a reply at the address it has stored. Most often the router handed the printer a new IP after a reboot, the printer dropped into deep sleep, or someone ticked the offline option by hand.

Fix it

1. Open Settings → Bluetooth & devices → Printers & scanners, select your printer, choose Open print queue, then in the Printer menu clear Use Printer Offline and Pause Printing.
2. Cancel every document sitting in the queue.
3. Print the network configuration page from the printer panel and compare its IP with the one Windows uses (Printer properties → Ports). If they differ, that's your answer.
4. Remove the printer and add it again, or add a new Standard TCP/IP port pointing at the current address.
5. In your router's settings, reserve that address for the printer's MAC so it stops changing. This is the fix that makes it stay fixed.
6. Restart the spooler: press Win + R, run services.msc, right-click Print Spooler → Restart.
7. If it only goes offline after idle periods, turn off the printer's deep-sleep timer in the embedded web server, and untick power-saving on your PC's network adapter.

A printer connected to a guest network, a mesh extender with its own SSID, or a VPN-protected PC will look offline even though everything works. Get both devices onto the same network first.

Fix it

1. Confirm the Mac and printer are on the same Wi-Fi network — not one on 5 GHz guest and the other on 2.4 GHz main.
2. Go to System Settings → Printers & Scanners, delete the printer, then add it again and pick the AirPrint or Secure AirPrint driver where offered. It usually behaves better than a vendor driver.
3. Still missing? Right-click inside the printer list and choose Reset printing system. This wipes every printer, queue and preset, so re-add them afterwards.
4. On iPhone or iPad, turn off Private Wi-Fi Address for your home network — it blocks discovery on some routers.
5. Delete leftover print queues after a macOS upgrade; stale queues from two versions ago fail quietly.

Clear a stuck spooler (Windows)

1. Open services.msc and stop the Print Spooler service.
2. Delete everything inside C:\Windows\System32\spool\PRINTERS — the folder itself stays, the files go.
3. Start the Print Spooler service again.
4. Set the correct printer as default; Windows quietly redirects jobs to a PDF writer or a printer you removed months ago.
5. Send one single-page test document.

If the queue clears but still nothing appears

• The job may be waiting on a paper-size mismatch — the panel will be asking a question no one answered.
• Check the document isn't set to a tray your printer doesn't have.
• Print from a different application. A single corrupt file can stall the whole queue.

Clear it safely

1. Switch off and unplug before reaching inside. The carriage and fuser can move or be hot.
2. Pull jammed paper slowly in the direction it was travelling, using both hands so it doesn't tear. Torn scraps are what cause the second jam.
3. Open the rear access door or remove the duplexer and check the return path — a common hiding place.
4. Look for a torn corner, a stuck label, a shipping tape strip, or a stray staple against a roller. Nine times out of ten, an invisible jam is a fragment or a blocked sensor.
5. Wipe the pickup rollers with a lint-free cloth lightly dampened with distilled water. Let them dry fully before reconnecting power.

Stop it happening again

• Fan the stack before loading, and don't fill past the tray's line.
• Set the guides snug against the paper — not pinching, not loose.
• Match the tray's paper size setting to what's actually loaded.
• Store paper flat and sealed. Damp, curled paper jams repeatedly no matter what you clean.

Fix it

1. Print the print quality diagnostic page from the printer menu. It shows which colour channel is failing so you're not cleaning blindly.
2. Run Clean Printhead once, then print the test page again.
3. If it improved but isn't perfect, run it once more — then stop. Repeated cleaning cycles burn a surprising amount of ink and rarely help after the second pass. Leave the printer switched on for a few hours so the solvent can soften the block, then retest.
4. Run Align Printhead to fix doubled or fuzzy edges.
5. Check the media setting matches the paper. Photo settings on plain paper produce smearing; plain settings on photo paper produce dull, flat colour.
6. On Smart Tank and continuous-ink models, confirm the ink valve is open and no air gap sits in the tubes.

A colour that is completely absent after two cleaning cycles usually means a blocked or failed printhead, not an empty cartridge. On models with an integrated head, that means a new cartridge; on models with a separate head, it's a service job.

Fix it

1. Remove the toner cartridge and rock it gently side to side to redistribute the toner, then refit. This buys real pages from a "low toner" cartridge.
2. Turn off EconoMode in Printing Preferences or the printer's embedded web server — it's the usual reason everything prints grey.
3. Reset print density to default; someone lowering it is a frequent culprit on shared office printers.
4. Measure the gap between repeating marks. A consistent interval identifies which roller or drum is damaged, which tells you the part to replace instead of replacing everything.
5. Toner that smudges off with a finger points to a fuser problem or a media type set to Heavy or Labels when plain paper is loaded.
6. Vertical white streaks in the same place each time usually mean toner has run down one side — or debris on the transfer roller.

Fix it

1. Switch the printer off and on with the cartridges installed — this alone clears a lot of false errors.
2. Take the cartridge out and check the protective tape and orange pull-tab are completely removed. Handle it by the sides only; never touch the copper contacts or the nozzle plate.
3. Wipe the contacts on the cartridge and inside the carriage with a dry lint-free cloth. Don't use alcohol or water on the chip.
4. Refit until it clicks firmly into place. A cartridge that sits a millimetre proud reads as missing.
5. Install a cartridge you know works to identify which one is actually at fault.
6. Check the cartridge number and regional code match your model. Cartridges bought for a different region are frequently rejected.

Refilled and third-party cartridges can be blocked by cartridge-protection settings or after a firmware update. If a previously working cartridge stopped being accepted, check whether the firmware changed — and be aware that using non-original supplies may affect your warranty terms.

Fix it

1. Most home printers only join 2.4 GHz networks. If your router broadcasts one name for both bands, temporarily split them, or connect during setup while your phone is on 2.4 GHz.
2. Use the panel's Wireless Setup Wizard and select your network by name rather than relying on a button-press method.
3. If setup won't start, restore the printer's network defaults from the panel, then set it up again from scratch.
4. Switch the router's security to WPA2 or WPA2/WPA3 mixed mode. WPA3-only networks and hidden SSIDs break discovery on older printers.
5. Turn off any VPN on the computer during setup — it hides the printer from the local network.
6. Move the printer away from microwaves, cordless phone bases and thick masonry walls; a weak signal shows up as random disconnects rather than an obvious failure.
7. Finish by reserving the printer's IP address in the router so it never shifts again.

Fix it

1. Scan from the printer's own panel to a USB drive or folder. If that works, the scanner hardware is fine and the problem is on the computer.
2. Reinstall the full-feature driver. The basic driver that Windows installs automatically often has no scan support at all.
3. Restart the Windows Image Acquisition (WIA) service in services.msc.
4. For USB scanning, use a different port and cable, and connect directly rather than through a hub.
5. Streaks down every scan mean a dirty glass or a dirty ADF scan strip — clean with glass cleaner sprayed onto the cloth, never onto the glass itself.
6. Pages feeding crooked or double-feeding from the document feeder point to worn pickup rollers.

Windows is only relaying that the printer reported a problem — it doesn't know which one. The printer's own display holds the actual reason, so read that first.

Work through these

1. Close every cover and door fully, including the rear one.
2. Load paper and confirm the tray is seated properly.
3. Check no cartridge is missing, loose, or reporting empty.
4. Reseat the USB cable at both ends, or confirm the network connection is live.
5. Cancel all queued jobs and restart the print spooler.
6. Reinstall the current driver for your model.

Blank pages

• Protective tape still on a new cartridge, or a fully clogged printhead.
• A document whose first page is genuinely empty — check in print preview.
• Text set to white, or a template with the content on a hidden layer.
• On a laser: the sealing strip left in a new toner cartridge.

Slow printing

• Quiet mode roughly halves speed on many models — turn it off in the printer settings.
• Best or Maximum DPI quality is dramatically slower than Normal; use it only for photos.
• Two-sided printing pauses for ink to dry between sides.
• A weak Wi-Fi signal slows large jobs badly — test the same file over USB to compare.
• Very large images and PDFs with embedded fonts take time to process; printing as an image can be faster.

Fix it

1. Switch off and unplug. Open the cartridge access door.
2. Remove any paper, packing material or foam blocks from the carriage path — new printers often ship with restraints people miss.
3. Slide the carriage gently by hand from one end to the other. It should glide with light resistance and no grinding.
4. Look at the thin plastic encoder strip running behind the carriage. Ink or grease on it makes the carriage lose position. Wipe it with a dry lint-free cloth along its length — never scrub it, and never use solvent.
5. Reseat every cartridge until it clicks.
6. Plug directly into a wall socket and switch on so the carriage can re-home.

If it still stalls after a clean path and a proper power cycle, the drive belt or carriage motor is likely at fault — that's a service repair, not a home fix.