I am trying to compute raster zonal statistics using a TIFF and shp file. I am using WPS process extension for geoserver. I am trying to use the WPS request builder provided by my GeoServer installation under demos. I am trying to execute the process to see the output but I am getting the message in the second screenshot. My geoTiff file is 459 MB. I left it to wait for 45 minutes but the loading sign did not change. Am I doing something wrong?

The following are the screenshots:

.