Drone spin on itself

hello everyone , i have an issue that my drone spin on itself , always the same direction , am using an X configuration , i have checked the motors , ESC’s , but no problem , what can the problem be ?

am using a SIMULINK model , no PID , only controlling throttle , but still spin on itself

I have encounter this 2 times, once was easy to spot the motor mount tilted but the second is probably what is your issue, Check that the motor positions on your flight computer is correct. That the positions of the motor configuration for your airframe. I had the motors setup by using the test motor sequence but this is not a representation of the actual position. 1,4,2,3 clockwise from the right top

Am using this configuration