AA.COM won't click through
 

Trying to book PDX, DFW(layover in DFW), RTB, PDX.
when I try to click through the DFW-RTB segment, it looks like it is processing and then just brings me back to the same screen, I click again and it won't go through.

Ironically, I can book the reservation with miles just fine, but not with $$.

I tried using Google Flights and then clicked through to book at AA.COM, and it gave an error and say try again..

Thoughts?

I had this happen recently on a multi-city itinerary.

See if you can load up your itinerary in ITA Matrix and use BookWithMatrix.

If you're trying to do a multi-city trip where you start the next leg the same day you finished the previous leg, AA.com has been programmed to detect and block those sorts of same-day multi-city trips.

Yeah, that's the opposite of what usually happens, at least when the itinerary includes partner flights.

Exceedingly common with all-AA flights though. AA is perfectly happy to let you book an award flight with double connections and long layovers if you want a cheap miles price, and still go out of their way to prevent you from stringing together that exact same itinerary as a cash ticket if there's even a chance it breaks the fare.

ITA Matrix won't validate married segment inventory availability with multi-city bookings if the layover is short enough to qualify for booking on a single fare component (24 hours in this case). You have to be careful about trusting it's fare quotes in these cases as they may not be valid (EF can be used to check actual married segment availability). You can use advanced search options with ITA Matrix and specify AA flights (AA+, for example) for one-way or roundtrip bookings and it will show far more booking options than aa.com and will validate married segment availability on fare quotes in these cases.