Which version of CasparCG server are you running? The built-in NDI support started with version 2.3.0
It is possible to add NDI output via iVGA to some previous versions. See the wiki, for example https://github.com/CasparCG/help/wiki/Server%3A-Configuration and several posts in this forum such as https://casparcgforum.org/t/how-to-setup-caspar-config-to-utilize-video-input/3473/2