diff --git a/src/Squidex.Domain.Apps.Entities/Rules/Guards/RuleActionValidator.cs b/src/Squidex.Domain.Apps.Entities/Rules/Guards/RuleActionValidator.cs
index 68a8fc9c5..62e3947b5 100644
--- a/src/Squidex.Domain.Apps.Entities/Rules/Guards/RuleActionValidator.cs
+++ b/src/Squidex.Domain.Apps.Entities/Rules/Guards/RuleActionValidator.cs
@@ -116,9 +116,9 @@ namespace Squidex.Domain.Apps.Entities.Rules.Guards
                 errors.Add(new ValidationError("Access token is required.", nameof(action.AccessToken)));
             }
 
-            if (string.IsNullOrWhiteSpace(action.Author) && !string.IsNullOrWhiteSpace(action.Publication))
+            if (string.IsNullOrWhiteSpace(action.Author) && string.IsNullOrWhiteSpace(action.Publication))
             {
-                errors.Add(new ValidationError("Author or publication id is required.", nameof(action.Author), nameof(action.Publication)));
+                errors.Add(new ValidationError("Author or publication is required.", nameof(action.Author), nameof(action.Publication)));
             }
 
             if (string.IsNullOrWhiteSpace(action.Content))
@@ -128,7 +128,7 @@ namespace Squidex.Domain.Apps.Entities.Rules.Guards
 
             if (string.IsNullOrWhiteSpace(action.Title))
             {
-                errors.Add(new ValidationError("Title is required.", nameof(action.Content)));
+                errors.Add(new ValidationError("Title is required.", nameof(action.Title)));
             }
 
             return Task.FromResult<IEnumerable<ValidationError>>(errors);
diff --git a/tests/Squidex.Domain.Apps.Entities.Tests/Rules/Guards/Actions/MediumActionTests.cs b/tests/Squidex.Domain.Apps.Entities.Tests/Rules/Guards/Actions/MediumActionTests.cs
new file mode 100644
index 000000000..4500a4081
--- /dev/null
+++ b/tests/Squidex.Domain.Apps.Entities.Tests/Rules/Guards/Actions/MediumActionTests.cs
@@ -0,0 +1,85 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschränkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Squidex.Domain.Apps.Core.Rules.Actions;
+using Squidex.Infrastructure;
+using Xunit;
+
+namespace Squidex.Domain.Apps.Entities.Rules.Guards.Actions
+{
+    public class MediumActionTests
+    {
+        [Fact]
+        public async Task Should_add_error_if_access_token_is_null()
+        {
+            var action = new MediumAction { AccessToken = null, Author = "author", Title = "title", Content = "content" };
+
+            var errors = await RuleActionValidator.ValidateAsync(action);
+
+            errors.Should().BeEquivalentTo(
+                new List<ValidationError>
+                {
+                    new ValidationError("Access token is required.", "AccessToken")
+                });
+        }
+
+        [Fact]
+        public async Task Should_add_error_if_author_is_null()
+        {
+            var action = new MediumAction { AccessToken = "token", Author = null, Title = "title", Content = "content" };
+
+            var errors = await RuleActionValidator.ValidateAsync(action);
+
+            errors.Should().BeEquivalentTo(
+                new List<ValidationError>
+                {
+                    new ValidationError("Author or publication is required.", "Author", "Publication")
+                });
+        }
+
+        [Fact]
+        public async Task Should_add_error_if_title_null()
+        {
+            var action = new MediumAction { AccessToken = "token", Author = "author", Title = null, Content = "content" };
+
+            var errors = await RuleActionValidator.ValidateAsync(action);
+
+            errors.Should().BeEquivalentTo(
+                new List<ValidationError>
+                {
+                    new ValidationError("Title is required.", "Title")
+                });
+        }
+
+        [Fact]
+        public async Task Should_add_error_if_content_is_null()
+        {
+            var action = new MediumAction { AccessToken = "token", Author = "author", Title = "title", Content = null };
+
+            var errors = await RuleActionValidator.ValidateAsync(action);
+
+            errors.Should().BeEquivalentTo(
+                new List<ValidationError>
+                {
+                    new ValidationError("Content is required.", "Content")
+                });
+        }
+
+        [Fact]
+        public async Task Should_not_add_error_if_values_are_valid()
+        {
+            var action = new MediumAction { AccessToken = "token", Author = "author", Title = "title", Content = "content" };
+
+            var errors = await RuleActionValidator.ValidateAsync(action);
+
+            Assert.Empty(errors);
+        }
+    }
+}