Yeah it's probably along the lines of some interior face in there, double vertices, scale not applied, flipped normals, maybe triangles or Ngons, perhaps you have a solidify or bevel modifier that has too high a value and is throwing things off. Check for all of that in your geometry.
Yeah, I think Omar and An may be right. Enter edit mode and select all your geo then hit "m" to merge and select the "by distance option" . You could also try going into edit mode and going to the top menu in the 3D viewport and select mesh -> normals -> recalculate outside. Hopefully one of those will do the trick.
