I'm trying to book a multi city ticket with 2 'legs' (one of the legs has more than one stop) using AA's international partners for the most part. If I try and book using a multi-city ticket, AA shows me a sign saying 'sorry one of the fares is not available' and urges me to rebook at the screen where I'm supposed to input passenger information.

I can see the legs separately in one way searches, and indeed put holds on them, but those are separate PNRs. I know there are restrictions on multi-city itineraries, but I don't think my legs would fall under those restrictions. IIRC, I did make similar bookings in the past. Also, if the multi-city trip is forbidden, AA has a different error message (this message urges me to rebook).

[ This is an award flight, but I'm not sure that would make any difference]
Questions
1) Is there any way to work around this from the website except to book each leg separately?
2) Otherwise, can I call in and get AA to make the booking manually or even merge the 2 PNRs into one?

Thanks!

Are you able to provide your routing? There are some 3rd region routing rules that prevent booking as one award, and when one tries to price it out as a same-day multi city, the site crashes.

1: On the website, no. If not award, ITA Matrix, but can't do that for an award.
2: Yes, put the more detailed one on hold and call to add the other. I don't believe they can merge PNRs, just add to them. (This works as it's a partner award, and they can change those).

Based on what you're saying I'm guessing you're trying to combine an AA-only dynamic priced segment(s) on one of the legs with a partner award on the other legs of the multi-city search.

If that's the case then these two award types cannot be combined on the same PNR. That's why booking everything separately works fine, and when you initially search multi-city it will appear to work ok, but aa.com will error out once you click through when it tries to combine everything on the same PNR.

Thanks

My rough itinerary is via these 2 'legs'
1) South Asia -> FCO/BCN via middle east
2) FCO/BCN -> NYC via LHR. I tried to use AA for NYC-> LHR flight rather than BA because the taxes/fees for biz class award travel are much lower for AA itself than for BA. I can see where that would run up against the constraint you described.

But I switched to pure BA for the 2nd leg, so both legs are partner award flights, but it's still failing when I try and get a combined PNR. Haven't had time to wait on hold for a CSR yet. The 'fixed' price is 100K miles

Any further thoughts?

Just curious, what do you mean the fixed price is 100k miles? If you can get it to work your total should be 132.5k miles, assuming business class (75k for Asia-Europe + 57.5k for Europe-US). That would be the same regardless of whether it's booked on the same or two PNR's.

And in theory it should work even if you were using AA for the LHR-JFK. As long as FCO-LHR-JFK was booked together as a single leg (not FCO-LHR + LHR-JFK) then the AA space would be U which can be combined with partners.

I should have been clearer-- I'm coming from the Indian subcontinent. So 42.5 for India to Europe, then 57.5 for Europe to NYC. The price is the same either way. Unfortunately, AA's site doesn't allow merging these 2 legs together whether Europe to NYC is BA or a mix of BA and AA. Could be just a glitch of some sort, not the same as the case you cited.

I'll try doing South Asia -> LHR in one leg and LHR -> NYC in the 2nd, and see if that is allowed

Ah gotcha, when you said Asia I just assumed Asia 1/2 and not the Indian Subcontinent.

The only thing I can think of is that on a single award from US<>Indian Subcontinent, AA does not allow connections in both the Middle East and Europe. You can connect in just the ME or just Europe, but not both. This shouldn't be an issue, since you're not booking a single award, but I suppose it's possible there is some logic built into aa.com that causes such a routing to error out on the same PNR (even if it's built using 2 awards, which should be allowable).