Marina, a 45-year-old freelance copywriter, has relied on WhatsApp for her work and personal life for years.
But one day last month that abruptly changed when a call to a colleague did not go through properly. They tried Telegram - another messaging app popular in Russia - but that did not work either.
She was one of millions of Russians facing new restrictions imposed in mid-August by Russia's media regulator, Roskomnadzor, on calls made through the two platforms - the country's most popular apps.
The timing coincides with the rollout of a new "national messenger" app known as Max and created by a Russian firm closely controlled by the Kremlin.
Monthly user numbers of WhatsApp and Telegram are estimated to be 97 and 90 million respectively — in a country of 143 million people.
