the repetitive clicking sounds I am guessing here are the power supply shutting down. This will happen if the load is too high.
My guess is to check one of the following issues.
1.) 1.) The motor is wired wrong. You said you checked this and from the sounds of what you have said it seem like it is trying to move the motor when it is supose to , so on to the next option.
2.) 2.) The gear box is bound up I have heard of one other person that this has happened to he fixed the problem by removing the motor assembly from the box grabbing the gear with a big pair of pliers and forcing it to turn he said it made a pop sound then it seem to work fine. The gear is hard to turn but you should be able to turn it with enough force and you wil hear the motor spin fast. Remember not to turn the gear fast as it it does not turn fast when running normally and if you do spin it fast you might risk breaking something.
3.) 3.) The motor is burnt out. To test it. If you try step two and you have the motor out before you put it back in try connecting the motor to a car battery even though the car battery is only 12V it should run the motor fine it will just run a little slower than normal.
Please Let us know how it goes.
If you can run the machine until you hear the clicking then get the volt meter so that you can measure the voltage across the top two screws on the right side of the white terminal block it should measure 24VDC when things are running correctly. and it should always show 24VDC while the extruder Power key is on.
Let me know what you find

234 V between power supply black and white wires
Thx
I've verified all the wires again , no one is touching the case except the ground one