Merging cylindrical faces using ShapeUpgrade_UnifySameDomain

Is it possible to merge cylindrical faces of two bodies that are joined together. Currently it forms a seam which is undesired. I tried BRepAlgoAPI_Fuse to join two bodies and ShapeUpgrade_UnifySameDomain to merge faces. Bodies are joined but faces are not merged. Attaching the result I am getting. Does ShapeUpgrade_UnifySameDomain work only for coplanar faces? Any other way to merge faces? Thanks in advance.

BRepAlgoAPI_Fuse fuseOperation(allShapes[0], allShapes[1]);
fuseOperation.Build();
 
if (fuseOperation.IsDone())
{
    // Get result.
    TopoDS_Shape mergedShape = fuseOperation.Shape();
 
    ShapeUpgrade_UnifySameDomain sUnifier;
    sUnifier.Initialize(mergedShape, true, true, true);
    sUnifier.SetSafeInputMode(true);
    sUnifier.AllowInternalEdges(false);
    sUnifier.SetLinearTolerance(1.e-4);
    sUnifier.SetAngularTolerance(1.e-6);
    sUnifier.Build();
    TopoDS_Shape unifyShape = sUnifier.Shape();
}