diff --git a/src/AndreGoepel.AppFoundation.Hosting/packages.lock.json b/src/AndreGoepel.AppFoundation.Hosting/packages.lock.json
index 697ea8b..9e449e9 100644
--- a/src/AndreGoepel.AppFoundation.Hosting/packages.lock.json
+++ b/src/AndreGoepel.AppFoundation.Hosting/packages.lock.json
@@ -588,7 +588,7 @@
       "andregoepel.appfoundation": {
         "type": "Project",
         "dependencies": {
-          "AndreGoepel.AppFoundation.Core": "[1.8.0, )",
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.AppFoundation.MailService": "[1.8.0, )",
           "AndreGoepel.Design.Blazor": "[1.4.2, )",
           "AndreGoepel.Marten.Identity.Blazor": "[1.8.0, )",
@@ -603,6 +603,7 @@
       "andregoepel.appfoundation.mailservice": {
         "type": "Project",
         "dependencies": {
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.Marten.Configuration": "[1.0.1, )",
           "MailKit": "[4.17.0, )",
           "Marten": "[9.19.0, )",
diff --git a/src/AndreGoepel.AppFoundation.MailService/AndreGoepel.AppFoundation.MailService.csproj b/src/AndreGoepel.AppFoundation.MailService/AndreGoepel.AppFoundation.MailService.csproj
index 917177f..67c18bd 100644
--- a/src/AndreGoepel.AppFoundation.MailService/AndreGoepel.AppFoundation.MailService.csproj
+++ b/src/AndreGoepel.AppFoundation.MailService/AndreGoepel.AppFoundation.MailService.csproj
@@ -26,6 +26,10 @@
     <InternalsVisibleTo Include="AndreGoepel.AppFoundation.MailService.Tests" />
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\AndreGoepel.AppFoundation.Core\AndreGoepel.AppFoundation.Core.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="MailKit" />
     <PackageReference Include="Marten" />
diff --git a/src/AndreGoepel.AppFoundation.MailService/IEmailSettingsStore.cs b/src/AndreGoepel.AppFoundation.MailService/IEmailSettingsStore.cs
index ef80687..52ef676 100644
--- a/src/AndreGoepel.AppFoundation.MailService/IEmailSettingsStore.cs
+++ b/src/AndreGoepel.AppFoundation.MailService/IEmailSettingsStore.cs
@@ -1,3 +1,5 @@
+using AndreGoepel.AppFoundation.Core;
+
 namespace AndreGoepel.AppFoundation.MailService;
 
 /// <summary>
@@ -15,9 +17,10 @@ public interface IEmailSettingsStore
 
     /// <summary>
     /// Persists the settings. <paramref name="newPassword"/> replaces the stored
-    /// SMTP password; pass <c>null</c> or empty to keep the current one.
+    /// SMTP password; pass <c>null</c> or empty to keep the current one. Fails when
+    /// no password is stored yet and none is supplied.
     /// </summary>
-    Task SaveAsync(
+    Task<Result> SaveAsync(
         EmailSettings settings,
         string? newPassword,
         CancellationToken cancellationToken = default
diff --git a/src/AndreGoepel.AppFoundation.MailService/MartenEmailSettingsStore.cs b/src/AndreGoepel.AppFoundation.MailService/MartenEmailSettingsStore.cs
index e5512f1..334a54e 100644
--- a/src/AndreGoepel.AppFoundation.MailService/MartenEmailSettingsStore.cs
+++ b/src/AndreGoepel.AppFoundation.MailService/MartenEmailSettingsStore.cs
@@ -1,3 +1,4 @@
+using AndreGoepel.AppFoundation.Core;
 using AndreGoepel.Marten.Configuration;
 using Microsoft.AspNetCore.DataProtection;
 
@@ -28,7 +29,7 @@ public async Task<EmailSettings> LoadAsync(CancellationToken cancellationToken =
             : new EmailSettings();
     }
 
-    public async Task SaveAsync(
+    public async Task<Result> SaveAsync(
         EmailSettings settings,
         string? newPassword,
         CancellationToken cancellationToken = default
@@ -48,7 +49,7 @@ public async Task SaveAsync(
         }
         else
         {
-            throw new InvalidOperationException("An SMTP password is required for the first save.");
+            return Result.Fail("An SMTP password is required for the first save.");
         }
 
         await store.SaveAsync(
@@ -65,5 +66,7 @@ await store.SaveAsync(
             },
             cancellationToken
         );
+
+        return Result.Ok();
     }
 }
diff --git a/src/AndreGoepel.AppFoundation.MailService/packages.lock.json b/src/AndreGoepel.AppFoundation.MailService/packages.lock.json
index 4e5e955..6b6ce3a 100644
--- a/src/AndreGoepel.AppFoundation.MailService/packages.lock.json
+++ b/src/AndreGoepel.AppFoundation.MailService/packages.lock.json
@@ -225,6 +225,9 @@
           "WolverineFx": "6.22.0"
         }
       },
+      "andregoepel.appfoundation.core": {
+        "type": "Project"
+      },
       "Npgsql": {
         "type": "CentralTransitive",
         "requested": "[9.0.4, )",
diff --git a/src/AndreGoepel.AppFoundation/Components/Administration/Pages/EmailSettingsPage.razor b/src/AndreGoepel.AppFoundation/Components/Administration/Pages/EmailSettingsPage.razor
index 67bb141..4cd9874 100644
--- a/src/AndreGoepel.AppFoundation/Components/Administration/Pages/EmailSettingsPage.razor
+++ b/src/AndreGoepel.AppFoundation/Components/Administration/Pages/EmailSettingsPage.razor
@@ -3,6 +3,7 @@
 @attribute [Authorize(Roles = "Administrator")]
 @inherits AndreGoepel.AppFoundation.Components.LocalizedComponentBase
 
+@using AndreGoepel.AppFoundation.Core
 @using AndreGoepel.AppFoundation.MailService
 
 @inject IEmailSettingsStore SettingsStore
@@ -145,7 +146,7 @@
         isSaving = true;
         try
         {
-            await SettingsStore.SaveAsync(
+            var result = await SettingsStore.SaveAsync(
                 new EmailSettings
                 {
                     SenderName = model.SenderName,
@@ -159,21 +160,24 @@
                 string.IsNullOrEmpty(model.Password) ? null : model.Password
             );
 
-            hasPassword = true;
-            Input.Password = "";
-            NotificationService.Notify(
-                NotificationSeverity.Success,
-                T("EmailSettings.SavedNotificationTitle"),
-                T("EmailSettings.SavedNotificationMessage")
-            );
-        }
-        catch (Exception ex)
-        {
-            NotificationService.Notify(
-                NotificationSeverity.Error,
-                T("EmailSettings.ErrorSavingSettingsTitle"),
-                ex.Message
-            );
+            if (result.IsSuccess)
+            {
+                hasPassword = true;
+                Input.Password = "";
+                NotificationService.Notify(
+                    NotificationSeverity.Success,
+                    T("EmailSettings.SavedNotificationTitle"),
+                    T("EmailSettings.SavedNotificationMessage")
+                );
+            }
+            else
+            {
+                NotificationService.Notify(
+                    NotificationSeverity.Error,
+                    T("EmailSettings.ErrorSavingSettingsTitle"),
+                    result.Error
+                );
+            }
         }
         finally
         {
diff --git a/src/AndreGoepel.AppFoundation/packages.lock.json b/src/AndreGoepel.AppFoundation/packages.lock.json
index b974720..a301498 100644
--- a/src/AndreGoepel.AppFoundation/packages.lock.json
+++ b/src/AndreGoepel.AppFoundation/packages.lock.json
@@ -273,6 +273,7 @@
       "andregoepel.appfoundation.mailservice": {
         "type": "Project",
         "dependencies": {
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.Marten.Configuration": "[1.0.1, )",
           "MailKit": "[4.17.0, )",
           "Marten": "[9.19.0, )",
diff --git a/tests/AndreGoepel.AppFoundation.MailService.Tests/MartenEmailSettingsStore.Tests.cs b/tests/AndreGoepel.AppFoundation.MailService.Tests/MartenEmailSettingsStore.Tests.cs
index 28a180f..adbaaa6 100644
--- a/tests/AndreGoepel.AppFoundation.MailService.Tests/MartenEmailSettingsStore.Tests.cs
+++ b/tests/AndreGoepel.AppFoundation.MailService.Tests/MartenEmailSettingsStore.Tests.cs
@@ -1,3 +1,4 @@
+using AndreGoepel.AppFoundation.Core;
 using AndreGoepel.Marten.Configuration;
 using Microsoft.AspNetCore.DataProtection;
 using NSubstitute;
@@ -63,7 +64,7 @@ public async Task SaveAsync_WithNewPassword_StoresProtectedPassword()
         );
 
         // Act
-        await emailStore.SaveAsync(
+        var result = await emailStore.SaveAsync(
             new EmailSettings
             {
                 SenderName = "S",
@@ -75,6 +76,7 @@ await emailStore.SaveAsync(
         );
 
         // Assert
+        Assert.True(result.IsSuccess);
         Assert.NotNull(stored);
         Assert.NotEqual("new-secret", stored.ProtectedPassword);
         Assert.Equal(
@@ -101,7 +103,7 @@ public async Task SaveAsync_WithoutPassword_KeepsExistingProtectedPassword()
         );
 
         // Act
-        await BuildStore()
+        var result = await BuildStore()
             .SaveAsync(
                 new EmailSettings
                 {
@@ -114,26 +116,29 @@ await BuildStore()
             );
 
         // Assert
+        Assert.True(result.IsSuccess);
         Assert.NotNull(stored);
         Assert.Equal("protected", stored.ProtectedPassword);
     }
 
     [Fact]
-    public async Task SaveAsync_FirstSaveWithoutAnyPassword_Throws()
+    public async Task SaveAsync_FirstSaveWithoutAnyPassword_ReturnsFailure()
     {
-        // Act + Assert
-        await Assert.ThrowsAsync<InvalidOperationException>(() =>
-            BuildStore()
-                .SaveAsync(
-                    new EmailSettings
-                    {
-                        SenderName = "S",
-                        SenderEmail = "s@example.com",
-                        Server = "smtp",
-                        Username = "u",
-                    },
-                    newPassword: null
-                )
-        );
+        // Act
+        var result = await BuildStore()
+            .SaveAsync(
+                new EmailSettings
+                {
+                    SenderName = "S",
+                    SenderEmail = "s@example.com",
+                    Server = "smtp",
+                    Username = "u",
+                },
+                newPassword: null
+            );
+
+        // Assert
+        Assert.True(result.IsFailure);
+        Assert.Equal("An SMTP password is required for the first save.", result.Error);
     }
 }
diff --git a/tests/AndreGoepel.AppFoundation.MailService.Tests/packages.lock.json b/tests/AndreGoepel.AppFoundation.MailService.Tests/packages.lock.json
index 91c8fbf..200909a 100644
--- a/tests/AndreGoepel.AppFoundation.MailService.Tests/packages.lock.json
+++ b/tests/AndreGoepel.AppFoundation.MailService.Tests/packages.lock.json
@@ -359,9 +359,13 @@
           "xunit.v3.runner.common": "[3.2.2]"
         }
       },
+      "andregoepel.appfoundation.core": {
+        "type": "Project"
+      },
       "andregoepel.appfoundation.mailservice": {
         "type": "Project",
         "dependencies": {
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.Marten.Configuration": "[1.0.1, )",
           "MailKit": "[4.17.0, )",
           "Marten": "[9.19.0, )",
diff --git a/tests/AndreGoepel.AppFoundation.Tests/Components/Administration/EmailSettingsPage.Tests.cs b/tests/AndreGoepel.AppFoundation.Tests/Components/Administration/EmailSettingsPage.Tests.cs
index 8bec6a2..4fc6b11 100644
--- a/tests/AndreGoepel.AppFoundation.Tests/Components/Administration/EmailSettingsPage.Tests.cs
+++ b/tests/AndreGoepel.AppFoundation.Tests/Components/Administration/EmailSettingsPage.Tests.cs
@@ -1,4 +1,5 @@
 using AndreGoepel.AppFoundation.Components.Administration.Pages;
+using AndreGoepel.AppFoundation.Core;
 using AndreGoepel.AppFoundation.MailService;
 using Bunit;
 using Microsoft.AspNetCore.Authorization;
@@ -13,13 +14,14 @@ public sealed class EmailSettingsPageTests : BunitContext
 {
     private readonly IEmailSettingsStore store = Substitute.For<IEmailSettingsStore>();
     private readonly IEmailSender emailSender = Substitute.For<IEmailSender>();
+    private readonly NotificationService notificationService = new();
 
     public EmailSettingsPageTests()
     {
         JSInterop.Mode = JSRuntimeMode.Loose;
         Services.AddSingleton(store);
         Services.AddSingleton(emailSender);
-        Services.AddSingleton(new NotificationService());
+        Services.AddSingleton(notificationService);
     }
 
     private static EmailSettings Settings() =>
@@ -55,6 +57,9 @@ public void Submit_WithValidInput_SavesWithoutPasswordChange()
     {
         // Arrange
         store.LoadAsync(Arg.Any<CancellationToken>()).Returns(Settings());
+        store
+            .SaveAsync(Arg.Any<EmailSettings>(), Arg.Any<string?>(), Arg.Any<CancellationToken>())
+            .Returns(Result.Ok());
         var cut = Render<EmailSettingsPage>();
 
         // Act
@@ -74,6 +79,30 @@ public void Submit_WithValidInput_SavesWithoutPasswordChange()
         );
     }
 
+    [Fact]
+    public void Submit_StoreReturnsFailure_ShowsErrorNotificationWithResultMessage()
+    {
+        // Arrange
+        store.LoadAsync(Arg.Any<CancellationToken>()).Returns(Settings());
+        store
+            .SaveAsync(Arg.Any<EmailSettings>(), Arg.Any<string?>(), Arg.Any<CancellationToken>())
+            .Returns(Result.Fail("An SMTP password is required for the first save."));
+        var cut = Render<EmailSettingsPage>();
+
+        // Act
+        cut.Find("form").Submit();
+
+        // Assert
+        cut.WaitForAssertion(() =>
+            Assert.Contains(
+                notificationService.Messages,
+                message =>
+                    message.Severity == NotificationSeverity.Error
+                    && message.Detail == "An SMTP password is required for the first save."
+            )
+        );
+    }
+
     [Fact]
     public void Route_IsAdministrationEmailSettings_AndRequiresAdministratorRole()
     {
diff --git a/tests/AndreGoepel.AppFoundation.Tests/packages.lock.json b/tests/AndreGoepel.AppFoundation.Tests/packages.lock.json
index c0a866a..b549563 100644
--- a/tests/AndreGoepel.AppFoundation.Tests/packages.lock.json
+++ b/tests/AndreGoepel.AppFoundation.Tests/packages.lock.json
@@ -728,7 +728,7 @@
       "andregoepel.appfoundation": {
         "type": "Project",
         "dependencies": {
-          "AndreGoepel.AppFoundation.Core": "[1.8.0, )",
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.AppFoundation.MailService": "[1.8.0, )",
           "AndreGoepel.Design.Blazor": "[1.4.2, )",
           "AndreGoepel.Marten.Identity.Blazor": "[1.8.0, )",
@@ -744,7 +744,7 @@
         "type": "Project",
         "dependencies": {
           "AndreGoepel.AppFoundation": "[1.8.0, )",
-          "AndreGoepel.AppFoundation.Core": "[1.8.0, )",
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.AppFoundation.MailService": "[1.8.0, )",
           "AndreGoepel.AppFoundation.ServiceDefaults": "[1.8.0, )",
           "AndreGoepel.Marten.Configuration": "[1.0.1, )",
@@ -762,6 +762,7 @@
       "andregoepel.appfoundation.mailservice": {
         "type": "Project",
         "dependencies": {
+          "AndreGoepel.AppFoundation.Core": "[1.9.0, )",
           "AndreGoepel.Marten.Configuration": "[1.0.1, )",
           "MailKit": "[4.17.0, )",
           "Marten": "[9.19.0, )",