Re: Cartridge error and wireless lights blinking

@tsentalovich, Welcome to HP Support Community. 

Thank you for posting your query, I will be glad to help you. 
When both the cartridge error light and the wireless light are blinking on your HP DeskJet 3755 All-in-One Printer, it usually indicates a cartridge issue combined with a network/wireless setup problem. Here’s how you can troubleshoot both:

🔧 1. Fix the Cartridge Error

A blinking cartridge light typically means:

• Cartridges are not installed properly.
• Cartridges are empty, clogged, not genuine, or expired.
• There's a problem with the cartridge contacts.

✅ Steps to Fix:

1. Power off the printer and unplug it.
2. Open the cartridge access door and remove both cartridges.
3. Check for protective tape – make sure it’s removed (if new).
4. Gently clean the copper contacts on the cartridge and in the printer using a lint-free cloth and a bit of distilled water or isopropyl alcohol.
5. Let them dry, then reinsert the cartridges firmly.
6. Plug in and turn on the printer again.

🔁 If the issue persists, try replacing the cartridge (especially if it's third-party or refilled).

📶 2. Fix the Wireless Blinking Light

A blinking blue wireless light means the printer is not connected to Wi-Fi.✅ Steps to Reconnect:

1. Restore Wi-Fi Setup Mode:
   • Press and hold the Wireless and Cancel buttons together for about 5 seconds until the wireless light starts blinking.
2. Connect via HP Smart App:
   • Download or open the HP Smart app on your phone or PC.
   • Add your printer by following the instructions.
   • Select your Wi-Fi network and enter the password when prompted.

⚠️ If your wireless router has both 2.4GHz and 5GHz bands, make sure you're connecting the printer to the 2.4GHz network.
 

🛠️ If the Issue Persists:

• Run the HP Print and Scan Doctor (on Windows) to diagnose and fix issues.
• Try a printer reset by unplugging it for 60 seconds and then turning it back on.
• Update printer firmware using the HP Smart app.

I hope this helps. 

Take care and have a good day. 

Please click “Accepted Solution” if you feel my post solved your issue, it will help others find the solution. Click the “Kudos/Thumbs Up" on the bottom right to say “Thanks” for helping! 

Max3Aj

HP Support