Motor not spinning - Red LED

[Maleangel]

Hi everyone, really hope someone can help me solve this issue that arose today?
Dug my Spark out of lockdown, charged the batteries up, switched it all on but when I went to take off, only three motors spun, then obviously got the unable to take off error?
Brought it inside where it was darker and noticed now that when it’s turned on, there is a red light inside the shell in the corner of the non working motor, then the LED light under the motor lights up red. No movement or twitching of the motor at all?
Drone has never been crashed, barely used to be honest! Really disappointed me as I’ve got four DJI drones now as I thought they were the best out there! Hoping it’s an easy fix....... thanks for your help ??

 

[NOLADG]

Can you turn it easily with your hand? Maybe something got in it?

 

[Dragonfly Joe]

Follow NOLADG's good advice and see if the motor can be turned as easily as the three that are working. If it turns freely check the wiring to the motor. If it binds or requires more effort to turn the motor may need replacing. If you can solder the motors are easy to replace.