I just checked-in at a Courtyard earlier and they told me at check-in that my Marriott credit card was being read as invalid when they swiped it. When they typed it in the machine, it was the same thing. So they asked for a different credit card. This was weird because I just used it before checking-in and decided to use it at a restaurant after checking-in. Both before and after worked.
This happened to me as well two weeks back at a Fairfield Inn right across this property I am staying at. At first I thought it was a fluke but lightning shouldn't strike twice. Has something similar happened to other people when using their Marriott credit card?