Error in rasterizing a shapefile

I tried to convert a polygon shapefile of classified land cover to raster using ‘Rasterize (vector to raster) tool in GDAL. I chose the DN field, set output ratser size unit to pixels and chose the same layer extent as output extent. I get the following error:

GDAL command output:
*ERROR 1: Wrong value for -ts parameter.
Usage: gdal_rasterize [-b band]* [-i] [-at]
{[-burn value]* | [-a attribute_name] | [-3d]} [-add]
[-l layername]* [-where expression] [-sql select_statement]
[-dialect dialect] [-of format] [-a_srs srs_def] [-to "NAME=VALUE"]*
*[-co "NAME=VALUE"]* [-a_nodata value] [-init value]*
[-te xmin ymin xmax ymax] [-tr xres yres] [-tap] [-ts width height]
[-ot {Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/
CInt16/CInt32/CFloat32/CFloat64}] [-optim {[AUTO]/VECTOR/RASTER}] [-q]
<src_datasource> <dst_filename>**

What should I change to rasterize this polygon?