Not actually taking mail to Texas.

I was at the airport on my way to Texas. I handed the lady my boarding pass, she looked at it and frowned and told me to come with her. She took me to an information desk and asked another woman behind the counter something. Then she turned to me and said "Unfortunately we can't let you on this plane." I asked why, was there something wrong, did I need a new plane ticket? She told me it was because the plate mail I had in my carry-on was historically inaccurate.