Even manual booking is getting harder these days. It took me 3 calls to get YYZ-ORD-FRA-HEL that did not show up online.
First agent reluctantly ("we don't usually do this") agreed to check specific route I offered and then claimed it's illegal. HUACA. Second agent flat out refused going beyond simple O-to-D search. Another HUACA, and voila: route booked. I've had some clueless agents, but have never double HUACA'd before for a one-way.