According to an article from a leading Ethiopian news source, the Internet was shut down and the reason given by authorities was to prevent a leakage of exams papers.
Internet access was inaccessible across a large part of the country for three days. According to NetBlock, an organisation that monitors the web, access to the Internet in Ethiopia was totally cut off on Tuesday 11 June and there has only been an intermittent restoration of services since then.
This is not the first time Ethiopian authorities shut down the Internet to prevent exam papers being leaked. The article further suggests that considering the dire need of the Internet in everyday lives of citizens and businesses, the government must adopt and implement best practices from around the world to deal with exam leakages.