Snap to correct rotation

Hi , I have a mesh that is a little bit off in its rotation and I would like to correct it. Just made a plane and would like my mesh be resting on that plane.

It is not working I tried different snapping methods, maybe some of you could give me a tip or point out what I should do ?

Thank you!

For each snapping method, there are several options.
Inside snapping popover, you have to use Face method and enable Align Rotation to Target option.

You can also extend selection to target, hover rotation values of target in properties editor, do a right-click and choose Copy All to Selected in right-click menu.

I tried the first option and did not manage during the morning…now it works…of course its not Blender, but me.
Thank you!