The carousel transitions are not animated and therefore, are not sliding.
The slides are missing classes called
Due to the lack of these classes during transition, the slides are not animated. You can see this behaviour, while debugging the original carousel on the bootstrap documentation page https://getbootstrap.com/docs/4.0/components/carousel/#with-indicators
Link to minimally-working plunker that reproduces the issue:
Version of Angular, ng-bootstrap, and Bootstrap: