the important things to know before getting yourself too deep with routings, etc. are: total segment restrictions (16), continent restrictions (how many continents are you doing?), intra-continental segment restrictions (varies with continent), and inter-continental segment restrictions (again, depends)

without a firm understand of that "framework" you'll likely end up confused as to what you're doing wrong.

also, apparently the LONEx has a 21-day advance purchase? Did not realize that. Couldn't the OP buy a ticket with the first leg(s) 21+ days, then change the dates to the ones they want (assuming availability)?