It means that you are not protected. The fingerprint resistance failed. Firefox has very weak fingerprint resistance out of the box, I don't know why they advertise it as being effective. If your fingerprint is unique, it means every site you visit knows exactly who you are and share your visit and actions on that site with all their friends so that you can be tracked through the internet.
To be clear, a unique fingerprint doesn't have to mean you can be tracked. You can set up your browser to randomise attributes, which means you can have a unique fingerprint, but not an unusual fingerprint, and not the same fingerprint on any two visits. That way you can't be singled out from the other users who set up their browsers like this, and if done well, can't be singled out from any first-time visitor.