[SOLVED] OpenSceneGraph just cast shadow for one of the lights in the scene

I am trying to put different lights in a scene and have them cast shadows simultaneously. The problem is that every time I create a new osgShadow::ShadowMap for a light, the previous light stops casting shadow. I suspect that this has something to do with index or something, the same way every light has to have a setLightNum(x) defined. Below is the code used as reference for this image: .
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#include <iostream>
#include <osgViewer/Viewer>
#include <osgDB/ReadFile>
#include <osg/Node>
#include <osg/ref_ptr>
#include <osg/LightModel>
#include <osg/Geode>
#include <osg/ShapeDrawable>
#include <osg/Material>
#include <osg/Texture2D>
#include <osg/PositionAttitudeTransform>
#include <osg/Group>
#include <osg/MatrixTransform>
#include <osg/LightSource>
#include <osgShadow/ShadowedScene>
#include <osgShadow/ShadowMap>


#define LIGHT_CUTOFF_ANGLE 15
#define FILE_PATH_1 "tank.osg"
#define FILE_PATH_2 "rov.osg"


osg::Node* createLightSource(unsigned int num,
                             const osg::Vec3& trans,
                             const osg::Vec4& color)
{
    osg::ref_ptr<osg::Light> light = new osg::Light;
    light->setLightNum(num);
    light->setDiffuse(color);
    light->setPosition(osg::Vec4(0.0f, 0.0f, 0.0f, 1.0f));
    osg::ref_ptr<osg::LightSource> lightSource = new osg::LightSource;
    lightSource->setLight(light);
    osg::ref_ptr<osg::MatrixTransform> sourceTrans = new osg::MatrixTransform;
    sourceTrans->setMatrix(osg::Matrix::translate(trans));
    sourceTrans->addChild(lightSource.get());
    return sourceTrans.release();
}

int main(int argc, char const *argv[])
{
    // Set masks of shadow receivers and casters
    unsigned int rcvShadowMask = 0x1;
    unsigned int castShadowMask = 0x2;

    // Tank
    osg::ref_ptr<osg::MatrixTransform> tankNode = new osg::MatrixTransform;
    tankNode->addChild(osgDB::readNodeFile(FILE_PATH_1));
    tankNode->setMatrix(osg::Matrix::translate(0.0f, 0.0f, 0.0f));
    tankNode->setNodeMask(rcvShadowMask|castShadowMask);

    // ROV
    osg::ref_ptr<osg::MatrixTransform> rovNode = new osg::MatrixTransform;
    rovNode->addChild( osgDB::readNodeFile(FILE_PATH_2));
    rovNode->setMatrix(osg::Matrix::translate(5.0f, 5.0f, -1.0f));
    rovNode->setNodeMask(rcvShadowMask|castShadowMask);

    // Ambient light (taken from book)
    osg::ref_ptr<osg::LightSource> source0 = new osg::LightSource;
    source0->getLight()->setPosition(osg::Vec4(5.0, 5.0, 9.0, 0.0));
    source0->getLight()->setAmbient(osg::Vec4(0.2, 0.2, 0.2, 1.0));
    source0->getLight()->setDiffuse(osg::Vec4(0.8, 0.8, 0.8, 1.0));

    // We choose the famous and effective shadow mapping (osgShadow::ShadowMap) technique, and set its
    // necessary parameters including the light source, shadow texture's size, and unit:
    osg::ref_ptr<osgShadow::ShadowMap> sm0 = new osgShadow::ShadowMap;
    sm0->setLight(source0.get());
    sm0->setTextureSize(osg::Vec2s(1024, 1024));
    sm0->setTextureUnit(1);

    //Set the shadow scene's root node, and apply the technique instance, as well as shadow masks to it:
    osg::ref_ptr<osgShadow::ShadowedScene> root = new osgShadow::ShadowedScene;
    root->setShadowTechnique(sm0.get());
    root->setReceivesShadowTraversalMask(rcvShadowMask);
    root->setCastsShadowTraversalMask(castShadowMask);

    // Create a light state set
    osg::StateSet* state = root->getOrCreateStateSet();

/*     state->setMode(GL_LIGHTING, osg::StateAttribute::ON);
    state->setMode(GL_LIGHT0, osg::StateAttribute::ON); */
    state->setMode(GL_LIGHT1, osg::StateAttribute::ON);
/*     state->setMode(GL_LIGHT2, osg::StateAttribute::ON);
    state->setMode(GL_LIGHT3, osg::StateAttribute::ON); */

    // 1st Light Cone
     osg::ref_ptr<osg::Light> light1 = new osg::Light();
    light1->setAmbient(osg::Vec4(0.1, 0.1, 0.1, 0.5));
    light1->setPosition(osg::Vec4(4.0, 4.0, 9.0, 1.0));
    light1->setDirection(osg::Vec3(0, 0, -1)); 
    light1->setSpotCutoff(LIGHT_CUTOFF_ANGLE);
    light1->setLightNum(1);
    osg::ref_ptr<osg::LightSource> source1 = new osg::LightSource();
    source1->setLight(light1.get());

    // We may have many lights, but only one of them will cast shadows so far.
    // Uncomment the ShadowMap lines to see this behavior.
/*     osg::ref_ptr<osgShadow::ShadowMap> sm1 = new osgShadow::ShadowMap;
    sm1->setLight(source1.get());   
    sm1->setTextureSize(osg::Vec2s(1024, 1024));
    sm1->setTextureUnit(1);
    root->setShadowTechnique(sm1.get());  */

    // Add all models and the light source to the root
    root->addChild(tankNode.get());
    root->addChild(rovNode.get());
    root->addChild(source0.get());
    root->addChild(source1.get());

    // Start the viewer
    osgViewer::Viewer viewer;
    viewer.setSceneData(root.get());
    return viewer.run();
}
Why I am not getting a shadow for every light? What am I missing here?
Thank you in advance!