Iran has recovered oil export markets since sanctions ended last January. As it grapples with financial, political and diplomatic challenges, Tehran is struggling to sign energy deals, resolve payments issues and reintegrate with the global financial system. All must be overcome to make a true international comeback.

May proved to be a critical month for Iran on many fronts. The keenly-awaited decision by the US on 17 May to extend sanctions relief on Tehran, followed by the re-election of...