When you ask a question, the first answer is likely to be something that your competitors have also thought of. Generate a range of possibilities to consider.
The twice-Nobel Prize winner Linus Pauling said "To have a good idea, you first need to have a lot of ideas."
When you ask a question, people may think it is a test, or that there is one correct answer. Make it clear that you do not know the answer, and are looking for a whole range of answers. You need to preface your question with a "signal" that you are exploring the possibilities. For example, "I don't know what the answer to this question might be, but I think it's a way of getting us thinking differently about this issue…."
To increase the number of ideas generated, set a target number to be achieved. Ask for twenty ways to solve the challenge - this shows that you are serious about exploring the question. The first ten ideas are difficult to think of, but after that, people start to get more creative, and the ideas get more interesting. More people participate, and ideas are less likely to be dismissed, because they are needed in order to meet the target.
