Frame buffer not rendering depth into depth texture - c++

Question

So, i have this assignment about double pass rendering to compute shadows and I am trying to store the depth value of each of the objects of a scene and rendering them as a texture in another object.
I am using OpenGL, I don't really know where the error could be, but when analyzing a capture with RenderDoc, it says that the FBO (FrameBufferObject) is unused and also interprets what should be my 1st pass, a depth only pass, as a color pass.
/*-This is how I create the FBO and the texture to render the depth-*/
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);
// Create texture for Depth image (first pass)
glGenTextures(1, &depthTexture);
glBindTexture(GL_TEXTURE_2D, depthTexture);
// Give pixel data to opengl
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, 1024, 1024, 0, GL_DEPTH_COMPONENT, GL_UNSIGNED_BYTE, nullptr);
// WITH PCF for anti-aliasing shadow edges
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
glGenFramebuffers(1, &FBO);
glBindFramebuffer(GL_FRAMEBUFFER, FBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D,
depthTexture, 0);
glDrawBuffer(GL_NONE);
glReadBuffer(GL_NONE);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
/*---------------------------END------------------------------------*/
/*---This is how I render all the objects (1st and second pass)-----*/
glViewport(0, 0, 1024, 1024);
glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
cube.FirstPass(light.getPos());
plane.FirstPass(light.getPos());
cone1.FirstPass(light.getPos());
cone2.FirstPass(light.getPos());
glFlush();
glFinish();
glViewport(0, 0, WIDTH, HEIGHT);
glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
cube.display(&cam, light.getPos());
plane.display(&cam, light.getPos());
viewport.display(&cam, light.getPos());
cone1.display(&cam, light.getPos());
cone2.display(&cam, light.getPos());
/*---------------------------END------------------------------------*/
/*---------This is how I do First Pass---------*/
//Here goes first pass
glBindFramebuffer(GL_FRAMEBUFFER, sceneManager.getFBO());
glClear(GL_DEPTH_BUFFER_BIT);
glUseProgram(DepthPass.shader);
glm::mat4 mtx = glm::perspective(glm::radians(60.0f), 1024.0f / 1024.0f, 5.0f, 40.0f);
DepthPass.setMat("M", mtx * glm::lookAt(glm::vec3(lightPos.x, lightPos.y, lightPos.z), glm::vec3(0.0, 0.0, 0.0), glm::vec3(0.0, 1.0, 0.0)) *
getModelToWorld());
glBindVertexArray(vao);
// Draw
glDrawArrays(GL_TRIANGLES, 0, ModelVertices.size());
glBindFramebuffer(GL_FRAMEBUFFER, 0);
/*---------------------------END------------------------------------*/
/*--This is what I pass to the shader that shows the depth texture--*/
DepthPass.setFloat("near", 5.0f);
DepthPass.setFloat("far", 40.0);
DepthPass.setInt("IsViewport", 1);
glActiveTexture(GL_TEXTURE0);
//GetDepthTexture() returns a handle of the texture created before
glBindTexture(GL_TEXTURE_2D, sceneManager.GetDepthTexture());
std::string textureName = "depthTexture";
DepthPass.setInt(textureName.c_str(), sceneManager.GetDepthTexture());
/*---------------------------END------------------------------------*/