Hi @DOEEYANG,
Can you clarify how you are performing kriging? I'm guessing the Kriging tool in the Spatial Analyst toolbox, but there are a few different versions.
Without looking at your data, my guess is that these areas with no predictions are outside the neighborhood of your input points. Assuming you're using the tool above, check the "Search radius" parameter. If you are using a "Variable" neighborhood, check whether there is a "Maximum distance" value. If using a "Fixed" neighborhood, check the "Distance" value. If your cells with no predictions are further than this distance from any input point, the value cannot be interpolated. Using a sufficiently large distance should allow you to interpolate everywhere in your study area.
Please let me know if this does not resolve the problem or if you're using any of the kriging methods in Geostatistical Analyst.