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Brother HL-L8350CDW "Invalid Certificate" Error: What It Is and How to Fix It

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If you own a Brother HL-L8350CDW (or one of the closely related HL-L8260CDW, MFC-L8610CDW, or MFC-L8900CDW color lasers) and you've tried to print from a Mac running macOS Ventura or later, you've probably hit a frustrating wall: Brother HL-L8350CDW series will not print, invalid certificate. The print queue stalls, the printer doesn't move, and the error message doesn't really tell you what to do.

This isn't a broken printer. It's a security change Apple made in newer versions of macOS that broke the way older Brother printers authenticate over the network. Here's what's actually happening and how to get printing again.

What the Error Actually Means

Starting with macOS Ventura, Apple tightened the rules around printer drivers that use older AirPrint and IPP-over-HTTPS connections. The Brother HL-L8350CDW (released around 2014) uses a self-signed security certificate to identify itself on your network. macOS now flags any self-signed certificate as untrusted by default, and the print job sits in the queue waiting for a certificate that will never be approved.

The printer isn't doing anything wrong. The certificate isn't expired or counterfeit. It just doesn't meet the new bar macOS is enforcing.

Fix 1: Reset the Printing System and Re-Add the Printer

This works for most people and takes about three minutes:

  1. Open System Settings > Printers & Scanners.
  2. Right-click (or Control-click) anywhere in the printer list and choose Reset printing system. This removes every printer.
  3. Click the + button to add a printer.
  4. When the Brother HL-L8350CDW shows up, look at the Use dropdown at the bottom of the window. Change it from AirPrint (or Secure AirPrint) to Brother HL-L8350CDW CUPS.
  5. Click Add.

The key step is changing the driver from AirPrint to the older CUPS driver, which doesn't require the modern certificate. You may lose some advanced features like duplex auto-detection, but printing will work.

Fix 2: Add the Printer by IP Address Using LPD

If the CUPS driver doesn't show up in the dropdown, you can bypass AirPrint entirely:

  1. Print a network configuration page from the printer (Menu > Network > Network Reports > Network Configuration) and note the printer's IP address.
  2. In System Settings > Printers & Scanners, click +, then click the IP tab at the top of the window.
  3. Enter the printer's IP address. Set Protocol to Line Printer Daemon – LPD.
  4. Leave the Queue field blank. Choose Brother HL-L8350CDW CUPS from the Use dropdown (or browse to a downloaded driver from Brother).
  5. Click Add.

LPD is an older protocol that doesn't validate certificates at all, so it sidesteps the issue completely.

Fix 3: Update the Printer's Firmware

Brother quietly released firmware updates for several HL-L8350CDW-era printers that replaced the self-signed certificate with a newer one that macOS accepts. From a Windows computer or directly from the printer's web interface (type its IP address into a browser):

  1. Visit Brother's official downloads page, enter your exact model, and pick your operating system.
  2. Look for any "Firmware Update Tool" listed under Utilities.
  3. Run the tool. The printer will download new firmware and restart itself.
  4. After the update, try printing from your Mac again with the AirPrint driver.

This is the cleanest fix because it lets you keep using AirPrint with all its modern features. Not every model received an updated firmware, though, so if Brother doesn't list one for your specific printer, fall back to Fix 1 or 2.

Fix 4: Use IPP with the Updated CUPS Driver

If you still need duplex, scanning, and other advanced features, install Brother's standalone CUPS driver from their website (not the AirPrint version), then add the printer over IPP — not IPPS. The unencrypted IPP protocol doesn't require certificate validation.

You're losing the encrypted connection between your Mac and the printer, which matters on shared networks but is fine for a home office where the printer is on your own Wi-Fi. If you're in a corporate environment, talk to your IT team before going this route.

What About Windows Users?

Windows handles certificates differently and doesn't trigger this specific error. If you're on Windows 11 and the HL-L8350CDW won't print, the problem is usually a driver mismatch — reinstall the latest driver from Brother's site and the issue almost always clears up.

While You're Looking at the Printer…

The HL-L8350CDW uses Brother's TN-336 (standard) or TN-339 (super high yield) toner cartridges in CMYK, along with the DR-331CL drum unit. If you've had your printer for a while and you're already in there fixing the certificate issue, it's a good time to check your toner levels. We carry the full TN-336/TN-339 family along with our other Brother toner and ink supplies, and our printer-specific guides for related models like HL-L2350DW and MFC-L2710DW can help you confirm part numbers for other Brother lasers in your office.

Bottom Line

The "invalid certificate" error on Brother HL-L8350CDW printers running on modern macOS is a known compatibility issue, not a printer failure. Switching from AirPrint to CUPS or adding the printer over LPD will get you printing in about five minutes — and a firmware update from Brother will restore AirPrint if one exists for your model.

Written and reviewed by — Founder of Castle Ink, 20+ years in the printer & imaging supplies industry.

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