What is the meaning of an empty SHAP graph in Explainable AI?

Using Python, I created a neural network to perform predictions on a binary class dataset (e.g. will a passenger survive the Titanic?). I am using the SHAP package to explain individual predictions. For all of the instances in this dataset, the visualization outputted by SHAP has an output value of 0 and the higher/lower graph is empty (there are no features listed).

shap.force_plot(k_explainer.expected_value[0], k_shap_values[0], label_test_X.iloc[0])

When I use a different dataset and run the line above, SHAP outputs a graph and lists features.

What does an empty SHAP graph mean, especially in this case where there is an empty graph for each instance of a dataset? I am reading the documentation to help understand this situation, but I appreciate any insight into this.

Thank you in advance for the help!