This is the wrong place to post that question.
For support, go to the Operating System Forum your question applies to (Windows, MacOS, or Linux).
As NDI is not native to OBS Studio, I'm presuming you are talking about a NDI plugin, in which case,
For all plugins, the best place to ask is within the Discussion thread for the specific plugin
https://obsproject.com/forum/resources/
Beware, being Free, Open Source software, the community typically expects users to RTFM ahead of time (read the manual). So to avoid nasty responses, be sure to read available plugin installation documentation, and recent discussions on installation related issues to see if your question is already answered. IF you still have a question, best to put in a LOT more info that what you posted above, including what you've already tried, and what exact issues you are having
Personally, I recommend making sure audio and video sources are working at Operating System level before even starting OBS Studio... make troubleshooting issues orders of magnitude easier
