diff --git a/src/problems_contact_2d_autodiff.jl b/src/problems_contact_2d_autodiff.jl
index f0252c4..44c9c26 100644
--- a/src/problems_contact_2d_autodiff.jl
+++ b/src/problems_contact_2d_autodiff.jl
@@ -225,7 +225,7 @@ function assemble!(problem::Problem{Contact}, time::Float64,
 
                     fc[:,slave_element_nodes] += w*la_s*N1'
                     fc[:,master_element_nodes] -= w*la_s*N2'
-                    gap[1,slave_element_nodes] += w*gn*Phi'
+                    gap[1,slave_element_nodes] += w*gn*Phi
                     #gap[1,slave_element_nodes] += w*gn*N1'
 
                 end # done integrating segment
diff --git a/test/test_contact_2d_finite_sliding.jl b/test/test_contact_2d_finite_sliding.jl
index f39d64f..624b30b 100644
--- a/test/test_contact_2d_finite_sliding.jl
+++ b/test/test_contact_2d_finite_sliding.jl
@@ -1,10 +1,12 @@
+# This file is a part of JuliaFEM.
+# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
+
 using JuliaFEM
 using JuliaFEM.Preprocess
 using JuliaFEM.Postprocess
 using JuliaFEM.Testing
 
 @testset "2d curved block with frictionless finite sliding contact using forwarddiff" begin
-    # FIXME: needs verification of some other fem software
     meshfile = Pkg.dir("JuliaFEM") * "/test/testdata/block_2d_curved.med"
     mesh = aster_read_mesh(meshfile)
 
@@ -49,10 +51,7 @@ using JuliaFEM.Testing
     normu = norm(contact.assembly.u)
     info("displacement vector norm = $normu")
 
-    # while accurate solution is unknown this is very close to linear solution
-    # sqrt( ((Stress 11 - Stress 22)^2 + (Stress 22 - Stress 33)^2 + (Stress 33-Stress 11)^2 + 6*(Stress 12^2 + Stress 23^2 + Stress 13^2))/2 )
-#   @test isapprox(normu, 0.49745873784105105)
-    @test isapprox(normu, 0.49745872893844145)
+    @test isapprox(normu, 0.4974792662500015; atol=1.0e-5)
 end
 
 #= TODO: Fix test, this is not converging