I'd contact Vizrt support if haven't, they would be the ones to assist with Connect NC2 issues.

You don't mention the version number, the first thing I do is verify that it is updated to 8-4-250519 (latest version). If I recall, there was a software build that shipped straight from the factory which had issues with NDI output. If you are on that build, updating will fix it.

https://www.vizrt.com/product-updates/viz-connect-family/