NoneType object is not iterable - Rasa Forms URGENT

Please go to this stack-overflow link as I need help with this URGENTLY. With many thanks!

Can you try changing your slot type to unfeaturized.

    type: unfeaturized
    auto_fill: false

It gives me a new error: Failed to extract slot “SEARCHCONTENT” with action form_action_file_search

Well, will this post remain unanswered?

        return {"SEARCHCONTENT": self.from_entity(entity="SEARCHCONTENT", intent=["file"])}

here you are mapping your slot to entity named SEARCHCONTENT that is extracted from intent file. Are you sure the entity is extracted properly and that the intent from which it was extracted is identified as file?