What’s the most common reason applicants for a security clearance are denied? Botched finances, the same one that causes those with clearances to lose them.

The reason is self-evident: Military personnel in deep debt are considered more open to bribes or accepting money in exchange for revealing secrets

Really not hard to put 2 and 2 together

https://www.debt.org/veterans/military-security-clearances/#:~:text=What’s the most common reason,in exchange for revealing secrets.