NaN in plotting graph?

While I am running Split step fourier method, Beyond a particular number of step, all the output becomes NaN and the graph is empty. Is this problem related to precession of the number used?

[Jan]

Can you provide any data and code, which reproduces the effect? details like "a particular number" are most likely useful to understand, what you do.

Please provide additional data by editing the question, such that the readers find all required information in one location.