Which of the following post is/was not served by António Guterres?

Secretary-General of the OPEC

Anto ́nio Manuel de Oliveira Guterres(2017- ) Portugal; former Prime Minister of Portugal from 1995 to 2002; was the United Nations High Commissioner for Refugees during 2005–2015; President of the Socialist International from 1999 to 2005. He is serving as the ninth Secretary–General of the United Nations.