I have the same problem with the short "rain-awning" over the entry door. It starts to retract, then abruptly stops. My fix has been to gently push on one of the two arms' elbows. One arm seems to hyper-extend when the awning is fully out, and will not bend to allow the awning to retract. Is there an adjustment somewhere that does not allow the elbows to get hyper-extended?
Although you did not state specifically, I am thinking the awning you are referring to is your main awning. But, anyways, these problems sound to be close enough for me to chime-in.