HP HP LaserJet M209dw printer refuses to print.

Printer refuses to print except a printer information page, that says:
your HP+ printer must be set up using the HP Smart app. Visit 123.hp.com to download the app and complete the guided setup. Any pages you have printed were intended for setup and have been exhausted. If you completed setup,  turn your printer off for at least a minute, then turn it back on. Wait a few minutes to let your printer status refresh and try to print again. visit hp.com/plus-support for additional setup help.
If I connect firefox to the printer at 192.168.1.126, the setup works, but it says:
Status: Set up the printer now.
  Refresh. Click this to refresh the device status.
Printer setup incomplete. Your HP+ printer must be set up using the HP Smart app. Visit 123.hp.com to download the app and complete the guided setup. Any pages you have printed were intended for setup and have been exhausted. If you completed setup, turn your printer off for at least a minute, then turn it back on. Wait a few minutes to let your printer status refresh and try to print again. Visit hp.com/plus-support for additional setup help.
I tried factory reset:
https://www.youtube.com/watch?v=H7rIYF6LyEY
Doesn't do the reset.
https://h30434.www3.hp.com/t5/Printer-Wireless-Networking-Internet/How-can-i-reset-laserjet-m209dw-to-the-factory-defaults/td-p/8366883
Press and hold the resume button on a printer turn the printer
ON and keep the button pressed for 15-20 seconds.
Changes nothing.
I use the setup app, which says, in Spanish, that setup is incomplete, to press + and follow the instructions. This does nothing. It does find the printer, I tap on it, and I am returned to the first screen.
How can I make this blasted printer print again?
If it is contract a support contract with HP to feed me supplies, I will take an axe and destroy the printer.
Anyway, it has the factory cartridge.
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Cheers,
        Carlos E.R.