Turkey claimed Mosul, then part of Iraq, as part of their "homeland." The League sent a commission to the city asking Mosuls which country they want to be a part of. Although they would rather be independent, they choose Iraq because a) it is a British client state, which offers them protection, and b) Mosul has a large Kurdish population, who don't like Turks. The League adopts their recommendation, and although Turkey disagrees with it the higher international court says they must. Independently Iraq (really Britain) and Turkey strike a deal giving Mosul to Iraq with a time limit of 25 years.
AMBIGUITY: ultimately successful but the League was unable to solve it without traditional diplomacy, i.e. sovereign states' negotiations.