The Russian space agency says it lost contact with an Angolan telecommunications satellite launched from the Baikonur Cosmodrome.
Roskosmos said that the launch on December 27 was successful but that ground control stopped receiving telemetric data from the satellite shortly after it entered orbit.
In a brief statement, it said officials were trying to restore contact with Angosat-1, the African country's first telecoms satellite.
The satellite was launched late on December 26 from the Russian-leased facility in Kazakhstan and separated from its booster rocket early on December 27.
Another failed launch would be a new blow to Moscow's space program on the heels of the unsuccessful launch of a satellite from Russia's new Vostochny facility in Siberia on November 28.
Vostochny, in the Amur region near the Chinese border, is intended to reduce Russia's dependence on Baikonur.
Deputy Prime Minister Dmitry Rogozin on December 27 told the Rossia 24 state TV channel that the November 28 failure had been caused by human error.
He said the rocket carrying the satellites had been programmed with the wrong coordinates, mistakenly having been given bearings for takeoff from Baikonur and not the actual one at Vostochny.
"The rocket was really programmed as if it was taking off from Baikonur," Rogozin said. "They didn't get the coordinates right."
The project has been dogged by reports of corruption, and one of the satellites put into orbit in its first launch, in April 2016, stopped functioning soon after it entered orbit.
With reporting by Interfax, AFP, and TASS