During this third attempt at a circumlunar mission, the Proton rocket’s second stage engine spuriously shut down at T+194.64 seconds due to a false signal from the payload which had erroneously detected a problem in the launch vehicle.
The emergency rescue system was activated and the 7K-L1 capsule was later successfully recovered about 323 miles (520 kilometers) from the launch pad, approximately 68 miles (110 kilometers) east of the town of Dzhezkazgan in Kazakhstan.
Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.