IGN WMS Server Raster - custom styling - SLD_BODY

Question

I currently use Leaflet as client of WMS server. I need to get MNT layer 1m. IGN WMS Server : https://wxs.ign.fr/altimetrie/geoportail/r/wms The layer I want to get is RGEALTI-MNT_PYR-ZIP_FXX_LAMB93_WMS. You can find the doc : https://geoservices.ign.fr/services-web-experts-altimetrie. I need a custom dynamic styling of this layer. I tried to use the argument SLD_BODY :

<StyledLayerDescriptor version="1.0.0"    xsi:schemaLocation="http://www.opengis.net/sld StyledLayerDescriptor.xsd"
        xmlns="http://www.opengis.net/sld"
        xmlns:ogc="http://www.opengis.net/ogc"
        xmlns:xlink="http://www.w3.org/1999/xlink"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
        <NamedLayer>
            <Name>RGEALTI-MNT_PYR-ZIP_FXX_LAMB93_WMS</Name>
            <UserStyle>
                <Title>SLD Cook Book: Simple polygon with stroke</Title>
                <IsDefault>1</IsDefault>
                <FeatureTypeStyle>
                    <Rule>
                        <RasterSymbolizer>
                            <Geometry>
                                <ogc:PropertyName>grid</ogc:PropertyName>
                            </Geometry>
                            <ColorMap  type="ramp">
                                <ColorMapEntry color="#30123b" quantity="8908597" label="8908597,0000" opacity="1.0"/>
                                <ColorMapEntry color="#321543" quantity="8917234.7707183" label="8917234,7707" opacity="1.0"/>
                            </ColorMap>
                            <ContrastEnhancement/>
                        </RasterSymbolizer>
                    </Rule>
                </FeatureTypeStyle>
            </UserStyle>
        </NamedLayer>  
</StyledLayerDescriptor>

I tried to make a random request with bbox but it return a black and white style, the default style. Is there a way to know if the WMS server support sld_body? What am I do wrong?