diff --git a/src/Utilities/results.jl b/src/Utilities/results.jl
index d1f199334d..d5d86ab368 100644
--- a/src/Utilities/results.jl
+++ b/src/Utilities/results.jl
@@ -52,6 +52,26 @@ end
 
 # MOI.DualObjectiveValue
 
+function _validate_function(
+    ::Type{F},
+    attr,
+    key,
+) where {
+    F<:Union{
+        MOI.VariableIndex,
+        MOI.ScalarAffineFunction,
+        MOI.VectorOfVariables,
+        MOI.VectorAffineFunction,
+    },
+}
+    return nothing
+end
+
+function _validate_function(::Type{F}, attr, key) where {F}
+    msg = "Cannot get the dual objective with $key function of type `$F`"
+    return throw(MOI.GetAttributeNotAllowed(attr, msg))
+end
+
 """
     get_fallback(
         model::MOI.ModelLike,
@@ -75,15 +95,10 @@ function get_fallback(
         throw(MOI.GetAttributeNotAllowed(attr, "No dual solution is available"))
     end
     F = MOI.get(model, MOI.ObjectiveFunctionType())
-    if !(F <: Union{MOI.VariableIndex,MOI.ScalarAffineFunction})
-        err = MOI.GetAttributeNotAllowed(
-            attr,
-            "Cannot get the dual objective with an objective function of type `$F`",
-        )
-        throw(err)
-    end
+    _validate_function(F, attr, "an objective")
     value = zero(T) # sum will not work if there are zero constraints
     for (F, S) in MOI.get(model, MOI.ListOfConstraintTypesPresent())
+        _validate_function(F, attr, "a constraint")
         value += _dual_objective_value(model, F, S, T, attr.result_index)::T
     end
     if MOI.get(model, MOI.ObjectiveSense()) != MOI.MAX_SENSE
diff --git a/test/Utilities/test_results.jl b/test/Utilities/test_results.jl
index 6b0c685dda..3ddd8ab59f 100644
--- a/test/Utilities/test_results.jl
+++ b/test/Utilities/test_results.jl
@@ -305,16 +305,59 @@ function test_get_fallback_DualObjectiveValue_Quadratic()
     MOI.set(model, MOI.PrimalStatus(), MOI.FEASIBLE_POINT)
     MOI.set(model, MOI.DualStatus(), MOI.FEASIBLE_POINT)
     MOI.set(model, MOI.VariablePrimal(), x, 0.0)
+    msg = "Cannot get the dual objective with an objective function of type `$(typeof(f))`"
     @test_throws(
-        MOI.GetAttributeNotAllowed(
-            MOI.DualObjectiveValue(),
-            "Cannot get the dual objective with an objective function of type `$(typeof(f))`",
-        ),
+        MOI.GetAttributeNotAllowed(MOI.DualObjectiveValue(), msg),
         MOI.Utilities.get_fallback(model, MOI.DualObjectiveValue(), T),
     )
     return
 end
 
+function test_get_fallback_scalar_nonlinear()
+    inner = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}())
+    model = MOI.Utilities.MockOptimizer(inner, Float64)
+    x = MOI.add_variable(model)
+    MOI.set(model, MOI.ObjectiveSense(), MOI.MIN_SENSE)
+    f = 1.0 * x
+    MOI.set(model, MOI.ObjectiveFunction{typeof(f)}(), f)
+    g = MOI.ScalarNonlinearFunction(:-, Any[x, 1.0])
+    c = MOI.add_constraint(model, g, MOI.GreaterThan(0.0))
+    MOI.set(model, MOI.ResultCount(), 1)
+    MOI.set(model, MOI.PrimalStatus(), MOI.FEASIBLE_POINT)
+    MOI.set(model, MOI.DualStatus(), MOI.FEASIBLE_POINT)
+    MOI.set(model, MOI.VariablePrimal(), x, 1.0)
+    MOI.set(model, MOI.ConstraintDual(), c, 1.0)
+    msg = "Cannot get the dual objective with a constraint function of type `$(typeof(g))`"
+    @test_throws(
+        MOI.GetAttributeNotAllowed(MOI.DualObjectiveValue(), msg),
+        MOI.Utilities.get_fallback(model, MOI.DualObjectiveValue(), Float64),
+    )
+    return
+end
+
+function test_get_fallback_vector_nonlinear()
+    inner = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}())
+    model = MOI.Utilities.MockOptimizer(inner, Float64)
+    x = MOI.add_variable(model)
+    MOI.set(model, MOI.ObjectiveSense(), MOI.MIN_SENSE)
+    f = 1.0 * x
+    MOI.set(model, MOI.ObjectiveFunction{typeof(f)}(), f)
+    g1 = MOI.ScalarNonlinearFunction(:-, Any[x, 1.0])
+    g = MOI.VectorNonlinearFunction([g1])
+    c = MOI.add_constraint(model, g, MOI.Nonnegatives(1))
+    MOI.set(model, MOI.ResultCount(), 1)
+    MOI.set(model, MOI.PrimalStatus(), MOI.FEASIBLE_POINT)
+    MOI.set(model, MOI.DualStatus(), MOI.FEASIBLE_POINT)
+    MOI.set(model, MOI.VariablePrimal(), x, 1.0)
+    MOI.set(model, MOI.ConstraintDual(), c, 1.0)
+    msg = "Cannot get the dual objective with a constraint function of type `$(typeof(g))`"
+    @test_throws(
+        MOI.GetAttributeNotAllowed(MOI.DualObjectiveValue(), msg),
+        MOI.Utilities.get_fallback(model, MOI.DualObjectiveValue(), Float64),
+    )
+    return
+end
+
 end  # module TestResults
 
 TestResults.runtests()