diff --git a/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/NamespaceBased/NamespaceBasedAuthorizationHelpers.cs b/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/NamespaceBased/NamespaceBasedAuthorizationHelpers.cs
index 5b82f1d7c2..9b3d3b6070 100644
--- a/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/NamespaceBased/NamespaceBasedAuthorizationHelpers.cs
+++ b/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/NamespaceBased/NamespaceBasedAuthorizationHelpers.cs
@@ -20,7 +20,7 @@ public static IList<string> GetClaimNamespacePrefixes(EdFiAuthorizationContext a
         if (!namespacePrefixes.Any() || namespacePrefixes.All(string.IsNullOrEmpty))
         {
             throw new SecurityAuthorizationException(
-                SecurityAuthorizationException.DefaultDetail + " The caller has not been configured correctly for accessing resources authorized by Namespace.",
+                SecurityAuthorizationException.DefaultTechnicalProblemDetail + " The caller has not been configured correctly for accessing resources authorized by Namespace.",
                 $"The API client has been given permissions on a resource that uses the '{authorizationStrategyName}' authorization strategy but the client doesn't have any namespace prefixes assigned.")
             {
                 InstanceTypeParts = ["namespace", "invalid-client", "no-namespaces"]
diff --git a/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/OwnershipBased/OwnershipBasedAuthorizationFilterDefinitionsFactory.cs b/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/OwnershipBased/OwnershipBasedAuthorizationFilterDefinitionsFactory.cs
index e70e665790..7ad0d8622b 100644
--- a/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/OwnershipBased/OwnershipBasedAuthorizationFilterDefinitionsFactory.cs
+++ b/Application/EdFi.Ods.Api/Security/AuthorizationStrategies/OwnershipBased/OwnershipBasedAuthorizationFilterDefinitionsFactory.cs
@@ -109,7 +109,7 @@ private InstanceAuthorizationResult AuthorizeInstance(
             return InstanceAuthorizationResult.Failed(
                 new SecurityAuthorizationException(
                     SecurityAuthorizationException.DefaultDetail + " The resource item is not owned by the caller.",
-                    $"The existing resource item has no 'OwnershipTokenId' value assigned and thus will never be accessible to clients using the '{authorizationStrategyName}' authorization strategy.")
+                    $"The existing resource item has no 'CreatedByOwnershipTokenId' value assigned and thus will never be accessible to clients using the '{authorizationStrategyName}' authorization strategy.")
                 { 
                     InstanceTypeParts = ["ownership", "invalid-data", "ownership-uninitialized"]
                 });
diff --git a/Application/EdFi.Ods.Tests/EdFi.Ods.Security/Authorization/NamespaceBasedAuthorizationTests.cs b/Application/EdFi.Ods.Tests/EdFi.Ods.Security/Authorization/NamespaceBasedAuthorizationTests.cs
index b74cc4f19e..ea916cfc36 100644
--- a/Application/EdFi.Ods.Tests/EdFi.Ods.Security/Authorization/NamespaceBasedAuthorizationTests.cs
+++ b/Application/EdFi.Ods.Tests/EdFi.Ods.Security/Authorization/NamespaceBasedAuthorizationTests.cs
@@ -28,15 +28,9 @@ public class NamespaceBasedAuthorizationStrategyTests
         public class SingleItemAuthorizationTests
         {
             [Test]
-            [TestCase(
-                AuthorizationPhase.ProposedData, 
-                "Access to the resource could not be authorized. The 'Namespace' value has not been assigned but is required for authorization purposes.",
-                $"{EdFiProblemDetailsExceptionBase.BaseTypePrefix}:security:authorization:namespace:access-denied:namespace-required")]
-            [TestCase(
-                AuthorizationPhase.ExistingData,
-                "Access to the resource could not be authorized. The existing 'Namespace' value has not been assigned but is required for authorization purposes.",
-                $"{EdFiProblemDetailsExceptionBase.BaseTypePrefix}:security:authorization:namespace:invalid-data:namespace-uninitialized")]
-            public void AuthorizationContextNamespaceIsEmpty_ShouldThrowAnException(AuthorizationPhase authorizationPhase, string expectedExceptionDetail, string expectedExceptionType)
+            [TestCase(AuthorizationPhase.ProposedData)]
+            [TestCase(AuthorizationPhase.ExistingData)]
+            public void AuthorizationContextNamespaceIsEmpty_ShouldThrowAnException(AuthorizationPhase authorizationPhase)
             {
                 //Arrange
                 var filterDefinitionsFactory = new NamespaceBasedAuthorizationFilterDefinitionsFactory(A.Fake<IDatabaseNamingConvention>());
@@ -71,18 +65,24 @@ public void AuthorizationContextNamespaceIsEmpty_ShouldThrowAnException(Authoriz
             
                 //Assert
                 var exception = (SecurityAuthorizationException)result.Exception.ShouldBeExceptionType<SecurityAuthorizationException>();
-                exception.Detail.ShouldContain(expectedExceptionDetail);
-                exception.Type.ShouldBe(expectedExceptionType);
+
+                if (authorizationPhase == AuthorizationPhase.ProposedData)
+                {
+                    exception.Detail.ShouldContain("Access to the resource could not be authorized. The 'Namespace' value has not been assigned but is required for authorization purposes.");
+                    exception.Type.ShouldBe($"{EdFiProblemDetailsExceptionBase.BaseTypePrefix}:security:authorization:namespace:access-denied:namespace-required");
+                }
+                else if (authorizationPhase == AuthorizationPhase.ExistingData)
+                {
+                    exception.Detail.ShouldContain("Access to the resource could not be authorized. The existing 'Namespace' value has not been assigned but is required for authorization purposes.");
+                    exception.Type.ShouldBe($"{EdFiProblemDetailsExceptionBase.BaseTypePrefix}:security:authorization:namespace:invalid-data:namespace-uninitialized");
+                    exception.Message.ShouldContain($"The existing resource item is inaccessible to clients using the 'NamespaceBased' authorization strategy because the 'Namespace' value has not been assigned.");
+                }
             }
 
             [Test]
-            [TestCase(
-                AuthorizationPhase.ProposedData,
-                "Access to the resource could not be authorized. The 'Namespace' value of the resource does not start with any of the caller's associated namespace prefixes ('uri://ed-fi.org/', 'uri://ed-fi-2.org/').")]
-            [TestCase(
-                AuthorizationPhase.ExistingData,
-                "Access to the resource could not be authorized. The existing 'Namespace' value of the resource does not start with any of the caller's associated namespace prefixes ('uri://ed-fi.org/', 'uri://ed-fi-2.org/').")]
-            public void NonMatchingNamespaceClaims_ShouldThrowAnException(AuthorizationPhase authorizationPhase, string expectedExceptionDetail)
+            [TestCase(AuthorizationPhase.ProposedData)]
+            [TestCase(AuthorizationPhase.ExistingData)]
+            public void NonMatchingNamespaceClaims_ShouldThrowAnException(AuthorizationPhase authorizationPhase)
             {
                 //Arrange
                 var filterDefinitionsFactory = new NamespaceBasedAuthorizationFilterDefinitionsFactory(A.Fake<IDatabaseNamingConvention>());
@@ -118,8 +118,10 @@ public void NonMatchingNamespaceClaims_ShouldThrowAnException(AuthorizationPhase
 
                 //Assert
                 var exception = (SecurityAuthorizationException)result.Exception.ShouldBeExceptionType<SecurityAuthorizationException>();
-                exception.Detail.ShouldContain(expectedExceptionDetail);
                 exception.Type.ShouldBe(string.Join(':', EdFiProblemDetailsExceptionBase.BaseTypePrefix, "security:authorization:namespace:access-denied:namespace-mismatch"));
+
+                string existingLiteral = authorizationPhase == AuthorizationPhase.ExistingData ? "existing " : string.Empty;
+                exception.Detail.ShouldContain($"Access to the resource could not be authorized. The {existingLiteral}'Namespace' value of the resource does not start with any of the caller's associated namespace prefixes ('uri://ed-fi.org/', 'uri://ed-fi-2.org/').");
             }
         }
 
@@ -158,7 +160,7 @@ public void EmptyNamespaceClaims_ShouldThrowAnException()
 
                 //Assert
 
-                exception.Detail.ShouldContain("Access to the resource could not be authorized. The caller has not been configured correctly for accessing resources authorized by Namespace.");
+                exception.Detail.ShouldContain("There was a problem authorizing the request. The caller has not been configured correctly for accessing resources authorized by Namespace.");
                 exception.Type.ShouldBe(string.Join(':', EdFiProblemDetailsExceptionBase.BaseTypePrefix, "security:authorization:namespace:invalid-client:no-namespaces"));
                 exception.Message.ShouldContain(
                     "The API client has been given permissions on a resource that uses the 'NamespaceBased' authorization strategy but the client doesn't have any namespace prefixes assigned.");
@@ -314,7 +316,7 @@ public void NoNamespaceClaims_ShouldThrowAnException()
                             AuthorizationPhase.ProposedData)));
 
                 // Assert
-                exception.Detail.ShouldContain("Access to the resource could not be authorized. The caller has not been configured correctly for accessing resources authorized by Namespace.");
+                exception.Detail.ShouldContain("There was a problem authorizing the request. The caller has not been configured correctly for accessing resources authorized by Namespace.");
                 exception.Type.ShouldBe(string.Join(':', EdFiProblemDetailsExceptionBase.BaseTypePrefix, "security:authorization:namespace:invalid-client:no-namespaces"));
                 exception.Message.ShouldContain(
                     "The API client has been given permissions on a resource that uses the 'NamespaceBased' authorization strategy but the client doesn't have any namespace prefixes assigned.");