How to do this Boolean Union

Logo Three Little Clouds ketting werkt niet.3dm (312.0 KB)

Hello, I need to Boolean Union these 2 closed extrusions but for some reason it doesn’t work.

When I extruded the curves from the clouds it said it has self-intersecting curves wich may cause an unwanted outcome, but it didn’t. I don’t know if it matter just thought it’d say it in case it does make a difference.

Thanks in advance

Although your lines could be (a lot) cleaner, here is a way to join the two shapes:

-extract all faces that are coincident (in front view for example drag around all faces where the shapes touch)
-delete these
-join the remaining polysurfaces
-cap the result

Better is though to start with cleaner lines, do the extrusion of the full shape, make extrusions of the cutouts and boolean these.