Here are the proven fixes that worked in 2021 and still work today.
Splinter Cell: Blacklist , released in 2013, was built during a transitional era for PC gaming. It utilized an older implementation of Ubisoft’s DRM that required a "handshake" with the Uplay client to launch. By 2021, Ubisoft had moved on. The Uplay client had evolved, eventually rebranding to Ubisoft Connect. The modern client no longer spoke the same dialect as the 2013 game. The uplay_r1.dll inside the game’s folder was effectively trying to call a phone number that had been disconnected. uplayr1dll splinter cell blacklist 2021