Originally Posted by
k374
The online tool allows you to choose sectors in which no flights are available no matter which date you choose. For example: Athens-Istanbul, this segment doesn't seem to be supported on any oneworld carrier but the tool allowed me to build the itinerary and then balked only when I went to choose the specific flight
Maybe it allowed you to build it into your itinerary originally because technically there is OW service between the two cities, with a stop (ie MAD, BUD, AMM, LHR) but then when you looked for flights either you selected 'direct flights only' or there was an error and connecting flights weren't displayed properly? Just a guess...