I'd try some baseline/simpler models on the same data and see how it performs. Maybe the model just can't do any better, that's always a good one to check before panicking.

You can also try to use K-means or DBSCAN or something like that, and try to get 2 clusters of results - see if those algos can segment your data better than your network. If so, maybe the network is set up incorrectly somehow, if not, maybe something funky happening to your data in pipeline.