Your itinerary is not valid
The web site sample itinerary is valid

There is a difference between inter-regional flights and intra-regional flights

An inter-regional flight is a flight that begins in one region and end in another region
An intra-regional flight is one that begins and ends in the same region

So, for example, MEL-SIN is inter-regional and SIN-KUL and KUL-HKG are intra-regional

Your itinerary has too many inter-regional flights between North-East Asia and South-East Asia (CTS-HKG, HKG-TPE and TPE-HKG)
Can you just fly CTS-NRT/HND-TPE? (these of course are intra-regional flights, not inter-regional)