I am thinking the clicking sound you are hearing is the motor's internal thermal circuit breaker.
I lubricate the motor shaft with WD-40 annually when the awning is put away for the winter. If I don't do that corrosion on the shaft makes it squeal when I run it in and out. If it has corroded to the point where it won't turn, it could cause what you are hearing.
If the shaft will not turn, the motor will over heat and trip off till it cools and then it will try again.
You might try lubricating the shaft with WD-40 and manually twist it to work the lube into the motor.
If it turns out you need a motor there is a used one for sale:
Dometic A & E power awning motor | eBay
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