it was short because erdogan decided to interfer in syria to destroy resistant line against israel, this is iranian government redline. when AKP came in power, they were so happy that islamists are in power. in many fields and goals they are thinking same like that. so iran didnt expect turkey to show hard reaction against israel like iran does. but when erdogan in Cooperation with west and US tried to change the syrian government( which means destroying resistent line against israel) the problem has been started. iran doesnt care to asad or its regime, she just cares to being anti US and israel.(atleast be neutral) so long as they have same goal. they can be united. just notice that, after AKP came in power, they improved economic ties and solved PKK issue in borders with iran,( they had joint military operation against them).
a united among muslim countries needs they have same goals in the world. look at EU. its possible if we just be more sane and grown enough to dont let others intrigue among us. we are one people. its in quran.
dawaa, problems between iran and turkey only make happy enemies,west countries, russians and... none of them never want to see progress in our region. to see a united among us.. because it would become their nightmare.
maybe right now it seems with low possibility, but i have hope to see this united one day.