Hi folks, just a question about the KTN. I travel the ORD - CPH route often and on my last trip I was able to enter my KTN and use the TSA- Pre check at ORD. Now I am flying again in May and it will not allow my KTN (combo of letters and numbers) though it seems to allow numbers only. Not sure how I was able to do it back last fall but it will not work for my May flight or the October flight I have scheduled. Thanks for the help.