HP Printer won't connect to my MacBook Pro

Thank you for the information.

Only drivers for up to macOS Sonoma 14 appear to be available via the support pages for the HP LaserJet Pro 400 M401a. For macOS 14, specifically HP Easy Start.

An HP Easy Admin utility can be tested if HP Easy Start cannot provide you with a suitable driver. This may or may not work for macOS Sequoia 15.

https://support.hp.com/us-en/document/c06164609

If necessary, you could also check whether a macOS generic PCL or postscript driver can be used.

https://support.hp.com/us-en/document/ish_4037000-4037075-16

Add a printer to your printer list so you can use it on Mac – Apple Support (UK)

Reset the printing system on your Mac to solve a problem – Apple Support (UK)

An HP LaserJet 400 m401a is listed as supported in https://developers.hp.com/hp-linux-imaging-and-printing/supported_devices/index.

If nothing else works, and if you would be prepared to carry out a few experiments with a little Linux-based Raspberry Pi (3) print server for AirPrint-like printing from a modern Mac (or iPhone, or iPad) with a USB printer, the replies by Techguyuk in connection with a Kyocera laser printer (Can’t print with iPadOS17 - Apple Community) could perhaps be of interest.

I suggest that you click on the link below where volunteers have written lot of driver for older non-supported printers. You may find one there which works. Good luck.

Gutenprint Supported Printers

Do you have one of the following exact models?

• HP LaserJet Pro 400 M401dn
• HP LaserJet Pro 400 M401dne
• HP LaserJet Pro 400 M401dw
• HP LaserJet Pro 400 M401n

If so, it appears to be a supported AirPrint printer.

About AirPrint - Apple Support

An AirPrint printer would not need additional drivers/software when connected wirelessly (Wi-Fi) or wired (Ethernet) to the same network (Wi-Fi router) as a Mac computer (or an iPhone/iPad). Would it be possible in this case to try a network connection instead of USB?