Does marriott app not let you use certificate, only if you book online?
This week Marriott.com was down, took me almost 2 hours to book a room (last minute while sitting in airport). Online wasn't working and only the app work sporadically. (actually got confirmation email, after I checked out.) Finally got room but wouldn't show options of certs only points. Didn't have choice as couldn't get online.
Booked with points, then waited another 1.5 for shuttle bus because they all full. Check in took another 30 min because they where doing everything by hand (had to show them my reservation number on my phone)
Called Marriott to have the points switched to cert, and they said nothing they can do as its after the stay......
All this was for a 15 hour trip....