Tried to book LAX-MIA-STL on AA but keep getting the message "We're sorry, we aren't able to confirm space on these partner flights. Please try again and choose different flights, dates or cities"

I've tried several dates and they show up as available. I get all the way to click "Purchase" and then get the error. Has anyone else seen this recently? I'm wondering if it's a temporary system-wide glitch to something specific to my routes.