Originally Posted by
Tobeornottobe
I did ask if I could do fly outbound to Lisbon instead. I was told yes, but computer said no!
Again that's not possible since the distance between LIS-MIA is greater than the distance between LHR-LIS. You have to find a routing where the distance from your landing airport (XXX)-MIA is less than MIA-LHR and LHR-XXX.