I looked at Fiamma troubleshooting and did not find anything that would help.
Whatever you try be cautious. I recently read a report of a Horizon awning (rebranded Fiamma) unfurling on its own when two RV techs were trying to fix a problem with it not wanting to open. The owner had it in for repair because he had to occasionally bump it with the heel of his palm a couple of times to get it to release. Don't work directly in its path.
If it were mine I'd unwind it a few turns then "bump" it a few times to see if it'll release.