<prompt> Human: The last update to my credit score was in October 2016. My score was 755. My score went from 755 to NA. I only have one card, but I use it monthly. I used to get all these credit card offers mailed to me and now I do not receive any. What could be the reasons for this issue? I checked all three of my credit reports and nothing seems out of the ordinary. Any help would be greatly appreciated. Thank you.  <response>: Dig deeper. The minimum credit score is 300, if yours it NA something is very wrong. 