After updating Unity to version 5.6.1f, there was a problem in the WebGL build.
Using
SceneManager.LoadScene or
SceneManagerLoadSceneAcynh A scene opens, but there are only objects on it that are DontDestroyOnLoad from the previous scene.
Those. the scene is empty, not even the camera, black screen. There are no errors, even with Develop and DebugSumbols.
I saw this in the English segment, but they didn’t answer the question https://forum.unity3d.com/threads/black-screen-when-changing-scene-in-webgl-using-unity-5-6.473367/