The text messaging service in Ethiopia has been shut down, the BBC's Kalkidan Yibeltal reports from the capital Addis Ababa.
The news comes as the country experiences its third day in a row with a break in online access.
The shutdowns on Tuesday and Wednesday both proved temporary.
The closure of the text messaging service coincides with nationwide exams. There has been speculation that the internet blackout is aimed at trying to stop people cheating, but this has not been confirmed by the authorities.
On Wednesday, the state broadcaster ETV reported that four students had been caught cheating after sending each other text messages.