Opposition leader Juan Guaido’s calls for Venezuelans to abandon Nicolas Maduro’s government are booming across the world outside, but the self-declared interim president is having a harder time delivering his message at home.

Watchdog groups in Venezuela and abroad say Guaido’s efforts to reach citizens via the internet have been hindered by the dominant provider — state-run CANTV — in a country where critical newspapers and broadcast media already have been muzzled.