Visa got rejected because Security Clearance

Hi, I'm seeking your advise about my below situation,

I have found a job in the education sector in Doha Qatar however once the employer applied for a Visa, it got rejected because security clearance, I'm a Dutch citizen and have no issues anywhere, the employer said he can't check the reason, how can I check my Security clearance status? What to do next? Which government Sector responsible for this matter? Any contact details?

Thanks!