I have had the same problem. If it is the same it just gets tight and hard to move. I did several things that are maintenance things ant it improved. Don't know which it was but my guess is with the spray grease.
I got it to open by getting up there and twisting on the roller tube to release tension while banging on the lever. Prob. same as you did. Once open I made sure that the awning fabric was centered on the roller tube, it slides best if wet. T got a popsicle stick if white lithium grease and greased every moving joint. Spray grease won't get enough grease in there. Wait to wipe it off until you extend and retract it a couple of times. While it is extended and lowered as much as possible spray a can of white lithium spray grease onto the holes in the tube on the lever side. Cover everything you can reach on the inside. Use a lot. Only a 20th of what comes will remain. A lot will run out so keep the fabric out of the way. When the drip stops then run it in and out most of the way few times and see how it works.
I did this routine as part of spring maintenance after that.
33' 2008 National Tropical on a Freightliner chassis.RVM#189