Barring pure girth of your route network [eventually the method we use to connect AM to greatcircle has a limit as to how many routes it can support] the most likely cause of route-map failure is simple.
"bogus" IATA codes.
In AM, at the moment we're solidly driven by IATA codes, however there are several airports in game which have no IATA code in real life, or a few that have shared IATA codes. we're making great progress towards a backend implementation of ICAO codes in addition to IATA, however we're still around 750 airports shy thereby presently no code outside of the submit airport page and a few admin airport related pages seriously support ICAO. Benefits of ICAO guided route maps would be that there's a set generic code for "airports without ICAO codes", it's ZZZZ. IATA has no such standard. also, some players know ICAO codes better then IATA ones. Furthermore, ICAO codes will [or are supposed to] never repeat [barring ZZZZ]. The only major drawback at the moment would be that the point at which your route map becomes too "full" to generate anymore is reduced by 25% [4 character ICAO code vs a 3 character IATA code]. The other, mildly embarassing fact, is as i mentioned before. At the moment, to update the list of "ignored" IATA codes in game requires updating about 4 or five files. with an updated multiworld code it will only take one page however we're still not ready [sadly] to roll out that code.
To continue expanded airport offerings, and to allow some players to fly into airports they know and love, we've allowed for the creation of bogus IATA codes [where plausible]. Unfortunately we can fall behind in updating our "do not pull" list for these codes due to the fact that it isn't as convenient as we'd like. Sorry.
If you can identify the code which are holding your route map back, and aren't mentioned above... i believe i can put up an update to the present airport code list on those pages... the more complete it can be, the better. And No. Iran is not the only country affected at the moment.