HP OfficeJet Pro 8120e Troubleshooting for Error UU_400_EB000A9900

[A_Gayathri]

The UU_400_EB000A9900 error on the HP OfficeJet Pro 8120e is usually related to a printer communication, setup, firmware, or network connectivity issue. This error commonly appears during printer setup, registration, or when the printer loses communication with the HP app or the network.

Recommended troubleshooting steps

1. Check printer setup

   • Power on the printer.
   • On the printer display, select your language and country/region.
   • Use the digital setup guide at hp.com/start/ojp8120e to complete printer setup, install ink, load paper, and install HP software. The HP software connects the printer to Wi‑Fi.
     
     

2. Make sure printer and PC are on the same network

   • If the network changed, remove the printer from Printers & scanners and then re-add it.
   • HP notes that the computer and printer must be connected to the same network for printing to work.
     
     

3. Check if the printer is reachable printing errors can occur when:

   • the printer is turned off or disconnected,
   • the PC and printer are on different networks,
   • the network configuration changed,
   • or the printer is in an error state such as paper jam or out of paper.
     
     

4. Open HP App for error details

   • If Windows shows a print error, click the error to open the HP app for more details and troubleshooting.
     
     

5. Reinstall the printer queue / HP UPA If printing still fails:

   • In Windows, open Printers & scanners.
   • Select the printer and click Remove.
   • Open HP App, right-click the printer, and click Hide Printer.
   • Add the printer again in HP App.
     
     

6. Reinstall HP UPA if needed

   • In Printers & scanners, select your printer and click Get app.
   • Microsoft Store opens.
   • Click Install.
   • After installation, verify the driver updated to HP UPA.
     
     

7. If ink-related messages appear, reseat or replace cartridges For the HP OfficeJet Pro 8120e:

   • Open the front door and lift the cartridge access door.
   • Wait until the carriage is idle and silent.
   • Push in on the tab to release the cartridge.
   • Remove and reinstall the cartridge in the correct color slot, or replace it if low/out of ink.
   • Close the cartridge access door and front door.

Related reason

• printer not reachable,
• printer and PC on different Wi‑Fi networks,
• network change,
• printer error state,
• driver/app issue requiring reinstall,
• or cartridge/setup issue.
  
  
  

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