device ownership password

Hi, there!

I just moved in to a new place, where there is a wireless network available, but when I tried to join it, it requires me a "device ownership password", which is supposed to be displayed or printed on the device, but I just cannot find it. There's a lot of numbers on many different labels on the computer, but every time I enter one of them, appears a message that says "checksum validation failed for the pin entered". So, which is that number I'm supposed to submit? How can I identify it?

Thanks a lot for your valuable help.