Because the nail has detected that your mobile phone has one of the following conditions: 1, you are using the simulator (developed clearly). 2. Your mobile phone is root. 3. You used virtual positioning software. 4. You did use the unofficial version of the nailing software (the signature is different from the official version). The first three are more likely, and the third is less likely.
Unofficial refers to things that do not belong to official organizations or institutions. Unofficial application refers to the application software developed and published by unofficial organizations or formal organizations.