Last night, I was trying to book a round trip to Lusaka. The AC site showed a couple of reasonable options, and with a priority award applied it said the entire round trip in J was 110K points.

I hit "book" ... and after entering the passenger details, it failed and I was shown an error message. This happened repeatedly, so I eventually called in to AP.

The woman who took the call could see the flights, tried to book them ... and it failed for her too. "Oh, I see what the problem is" she told me. "You're trying to use a priority reward with a partner airline. They don't like it when you do that, so they often won't release the seats to Air Canada. You should take the priority reward off, and it will book just fine"

That didn't sound exactly right to me, but I thanked her for her suggestion and hung up.

This morning everything booked without problem (online, and with the priority reward still applied).

I guess that's a case of HUTA (Hang Up Try Again?)