Every time there is a thread (of which there are increasing numbers now) about a flight being cancelled, several people will pipe up and say "claim on your travel insurance". 99 times out of 100 this situation is not covered under travel insurance.
It wastes everyone's time if claims are put in for this, yours and the travel insurers.
Generally (unless you have VERY expensive insurance), unless it's a weather issue, a strike or a mechanical issue, the airline cancelling is the responsibility of the airline, not of the travel insurer.
I know it's dull, but check your wording before submitting a claim. Yes, I might be a trifle weary from working in the industry over the last two years.