Zambia has restricted WhatsApp access as voting continues across the country to elect a new leader, according to Netblocks.
Netblocks tracks internet blockages, disruptions and shutdowns.
President Edgar Lungu of Patriotic Front is in a tight race with opposition rival Hakainde Hichilema of the United Party for National Development.
The Zambian government recently threatened to block the internet if people misbehave.
The government warned against social media abuse and sending of unconfirmed results.