Final Render is completely transparent

The final render delivers a completely transparent png, and also transparent video if I change png to FFmpeg. All the objects are enabled and there is light in the scene. This started three days ago and I don’t know why, because it worked perfectly before. I render in Cycles, and I’ve tried also EEVEE.
If I recover an AutoSave from 4 days ago, although I loss the progress I’ve made in these 4 days, it works.
In compositing everything is correctly connected.
Can anyone help me?
I know this is not an high priority error, because I can just animate what I’ve lost in a few hours, but I would like to know what was the error.
I have an environment texture and I’ve tried with and without the transparent film.
The project without most of the objects, also ends with the same result:

In the viewport it doesn’t have any problem, in rendered mode.

Which version of Blender you’re using?

The render window does not give us much information. Can you show the viewport on another workspace (layout, shading, etc)? Or share your blend file, if you can.

Initally, I would check if the objects are Enabled in Renders (the camera icon in the image bellow):

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Also, check if you’re not looking into a a different slot. Usually, the shortcut for those are the keys 1 to 8 (above the qwerty keys):

image