Expired Certificate Check Printer for Errors - Smart Tank 750 AIO

[ptbmac]

I have a Smart Tank 750 All-in-0ne which has worked flawlessly for 1 year while using macOSx 15 Sequoia.

I recently updated to macOSx 26 Tahoe.  The printer now has the error Expired Certificate.

I have diligently followed the instructions to create as self-signed certificate (4 times now), followed by rebooting the printer for the new certificate to take effect.  This has not worked. After repeated attempts, I still get the same Expired Certificate error. 

I set the printer up as a Generic PCL Laser Printer and it works fine for printing in B&W. 

What needs to be done to get my Smart Tank 750 AIO to work properly again?  Any help at all would be appreciated. 

[Hawks_Eye]

Hi @ptbmac 

Welcome to the HP Support Community! We're here to help you get back up and running.

To resolve the “Expired Certificate” error on your Smart Tank 750 AIO after updating to macOS 26 Tahoe, you’ll need to clear the expired encryption credentials and install a fresh certificate using the Embedded Web Server (EWS). This ensures secure communication with AirPrint and IPP protocols.

I’m really sorry this has disrupted your printing experience—especially after a year of flawless performance. It’s frustrating when a system update introduces unexpected roadblocks. 

Step-by-step actions to fix the Expired Certificate error

Access the Embedded Web Server (EWS)

• Make sure the printer is connected to the same network as your Mac.
• Open a browser and enter the printer’s IP address (found on the control panel or via the HP App).
• This opens the EWS interface.

Clear expired credentials

• In the EWS, go to Settings > Security > Encryption Credentials
• Select Delete Certificate or Clear Credentials
• Confirm and restart the printer

Create a new self-signed certificate

• In the same EWS section, choose Create Self-Signed Certificate
• Fill in the required fields (you can leave most as default)
• Save and apply the certificate
• Restart the printer again

Re-add the printer on macOS

• Go to System Settings > Printers & Scanners
• Remove the current printer entry
• Click Add Printer, select your Smart Tank 750, and choose AirPrint or Secure IPP as the protocol
• Avoid using Generic PCL unless needed for basic printing

Verify secure connection

• Print a test page from Safari or Preview
• If prompted about the certificate, choose Trust Always to avoid future warnings

This guide includes detailed steps for clearing and renewing certificates, tailored for macOS and iOS environments.

• HP Printers – Encryption Credentials Expired Error (macOS, iOS)

Let me know if the EWS interface doesn’t load or if the certificate still fails to apply—I’ll guide you through alternate setup methods. 

You’ve already done the hard part by identifying the root cause, and we’ll make sure your printer returns to full color and secure performance.

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Take care, and have an amazing day!

Regards, 

Hawks_Eye