Can you take any pictures, of your dish?
We have had some very high winds, in the UK, that could move some dishes.
Do you have access to a satellite meter? Even a cheap one?
Can you do a manual scan, of a few transponders, on each satellite, if there is no signal it will state no channels found, and if you use the clear before scan option you will get the N/A, instead of the channel name.
Your receiver is probably trying to find the data information, on each channel, and can't so produces N/A.