diff --git a/src/Microsoft.AspNetCore.SignalR.Core/DefaultHubLifetimeManager.cs b/src/Microsoft.AspNetCore.SignalR.Core/DefaultHubLifetimeManager.cs
index 9dadfc8986..ab5cbd926b 100644
--- a/src/Microsoft.AspNetCore.SignalR.Core/DefaultHubLifetimeManager.cs
+++ b/src/Microsoft.AspNetCore.SignalR.Core/DefaultHubLifetimeManager.cs
@@ -17,6 +17,16 @@ namespace Microsoft.AspNetCore.SignalR
 
         public override Task AddGroupAsync(string connectionId, string groupName)
         {
+            if (connectionId == null)
+            {
+                throw new ArgumentNullException(nameof(connectionId));
+            }
+
+            if (groupName == null)
+            {
+                throw new ArgumentNullException(nameof(groupName));
+            }
+
             var connection = _connections[connectionId];
             if (connection == null)
             {
@@ -36,6 +46,16 @@ namespace Microsoft.AspNetCore.SignalR
 
         public override Task RemoveGroupAsync(string connectionId, string groupName)
         {
+            if (connectionId == null)
+            {
+                throw new ArgumentNullException(nameof(connectionId));
+            }
+
+            if (groupName == null)
+            {
+                throw new ArgumentNullException(nameof(groupName));
+            }
+
             var connection = _connections[connectionId];
             if (connection == null)
             {
@@ -79,8 +99,18 @@ namespace Microsoft.AspNetCore.SignalR
 
         public override Task InvokeConnectionAsync(string connectionId, string methodName, object[] args)
         {
+            if (connectionId == null)
+            {
+                throw new ArgumentNullException(nameof(connectionId));
+            }
+
             var connection = _connections[connectionId];
 
+            if (connection == null)
+            {
+                return Task.CompletedTask;
+            }
+
             var message = new InvocationMessage(GetInvocationId(), nonBlocking: true, target: methodName, arguments: args);
 
             return WriteAsync(connection, message);
@@ -88,6 +118,11 @@ namespace Microsoft.AspNetCore.SignalR
 
         public override Task InvokeGroupAsync(string groupName, string methodName, object[] args)
         {
+            if (groupName == null)
+            {
+                throw new ArgumentNullException(nameof(groupName));
+            }
+
             return InvokeAllWhere(methodName, args, connection =>
             {
                 var feature = connection.Features.Get<IHubGroupsFeature>();
diff --git a/src/Microsoft.AspNetCore.SignalR.Redis/RedisHubLifetimeManager.cs b/src/Microsoft.AspNetCore.SignalR.Redis/RedisHubLifetimeManager.cs
index d6197dc5ea..b6185bbcab 100644
--- a/src/Microsoft.AspNetCore.SignalR.Redis/RedisHubLifetimeManager.cs
+++ b/src/Microsoft.AspNetCore.SignalR.Redis/RedisHubLifetimeManager.cs
@@ -175,6 +175,11 @@ namespace Microsoft.AspNetCore.SignalR.Redis
 
         public override Task InvokeConnectionAsync(string connectionId, string methodName, object[] args)
         {
+            if (connectionId == null)
+            {
+                throw new ArgumentNullException(nameof(connectionId));
+            }
+
             var message = new InvocationMessage(GetInvocationId(), nonBlocking: true, target: methodName, arguments: args);
 
             return PublishAsync(_channelNamePrefix + "." + connectionId, message);
@@ -182,6 +187,11 @@ namespace Microsoft.AspNetCore.SignalR.Redis
 
         public override Task InvokeGroupAsync(string groupName, string methodName, object[] args)
         {
+            if (groupName == null)
+            {
+                throw new ArgumentNullException(nameof(groupName));
+            }
+
             var message = new InvocationMessage(GetInvocationId(), nonBlocking: true, target: methodName, arguments: args);
 
             return PublishAsync(_channelNamePrefix + ".group." + groupName, message);
@@ -291,6 +301,16 @@ namespace Microsoft.AspNetCore.SignalR.Redis
 
         public override async Task AddGroupAsync(string connectionId, string groupName)
         {
+            if (connectionId == null)
+            {
+                throw new ArgumentNullException(nameof(connectionId));
+            }
+
+            if (groupName == null)
+            {
+                throw new ArgumentNullException(nameof(groupName));
+            }
+
             if (await AddGroupAsyncCore(connectionId, groupName))
             {
                 // short circuit if connection is on this server
@@ -361,6 +381,16 @@ namespace Microsoft.AspNetCore.SignalR.Redis
 
         public override async Task RemoveGroupAsync(string connectionId, string groupName)
         {
+            if (connectionId == null)
+            {
+                throw new ArgumentNullException(nameof(connectionId));
+            }
+
+            if (groupName == null)
+            {
+                throw new ArgumentNullException(nameof(groupName));
+            }
+
             if (await RemoveGroupAsyncCore(connectionId, groupName))
             {
                 // short circuit if connection is on this server
diff --git a/test/Microsoft.AspNetCore.SignalR.Tests/DefaultHubLifetimeManagerTests.cs b/test/Microsoft.AspNetCore.SignalR.Tests/DefaultHubLifetimeManagerTests.cs
new file mode 100644
index 0000000000..68acba4366
--- /dev/null
+++ b/test/Microsoft.AspNetCore.SignalR.Tests/DefaultHubLifetimeManagerTests.cs
@@ -0,0 +1,154 @@
+using System.Threading.Tasks;
+using System.Threading.Tasks.Channels;
+using Microsoft.AspNetCore.SignalR.Internal.Protocol;
+using Xunit;
+
+namespace Microsoft.AspNetCore.SignalR.Tests
+{
+    public class DefaultHubLifetimeManagerTests
+    {
+        [Fact]
+        public async Task InvokeAllAsyncWritesToAllConnectionsOutput()
+        {
+            using (var client1 = new TestClient())
+            using (var client2 = new TestClient())
+            {
+                var output1 = Channel.CreateUnbounded<HubMessage>();
+                var output2 = Channel.CreateUnbounded<HubMessage>();
+
+                var manager = new DefaultHubLifetimeManager<MyHub>();
+                var connection1 = new HubConnectionContext(output1, client1.Connection);
+                var connection2 = new HubConnectionContext(output2, client2.Connection);
+
+                await manager.OnConnectedAsync(connection1);
+                await manager.OnConnectedAsync(connection2);
+
+                await manager.InvokeAllAsync("Hello", new object[] { "World" });
+
+                Assert.True(output1.In.TryRead(out var item));
+                var message = item as InvocationMessage;
+                Assert.NotNull(message);
+                Assert.Equal("Hello", message.Target);
+                Assert.Single(message.Arguments);
+                Assert.Equal("World", (string)message.Arguments[0]);
+
+                Assert.True(output2.In.TryRead(out item));
+                message = item as InvocationMessage;
+                Assert.NotNull(message);
+                Assert.Equal("Hello", message.Target);
+                Assert.Single(message.Arguments);
+                Assert.Equal("World", (string)message.Arguments[0]);
+            }
+        }
+
+        [Fact]
+        public async Task InvokeAllAsyncDoesNotWriteToDisconnectedConnectionsOutput()
+        {
+            using (var client1 = new TestClient())
+            using (var client2 = new TestClient())
+            {
+                var output1 = Channel.CreateUnbounded<HubMessage>();
+                var output2 = Channel.CreateUnbounded<HubMessage>();
+
+                var manager = new DefaultHubLifetimeManager<MyHub>();
+                var connection1 = new HubConnectionContext(output1, client1.Connection);
+                var connection2 = new HubConnectionContext(output2, client2.Connection);
+
+                await manager.OnConnectedAsync(connection1);
+                await manager.OnConnectedAsync(connection2);
+
+                await manager.OnDisconnectedAsync(connection2);
+
+                await manager.InvokeAllAsync("Hello", new object[] { "World" });
+
+                Assert.True(output1.In.TryRead(out var item));
+                var message = item as InvocationMessage;
+                Assert.NotNull(message);
+                Assert.Equal("Hello", message.Target);
+                Assert.Single(message.Arguments);
+                Assert.Equal("World", (string)message.Arguments[0]);
+
+                Assert.False(output2.In.TryRead(out item));
+            }
+        }
+
+        [Fact]
+        public async Task InvokeGroupAsyncWritesToAllConnectionsInGroupOutput()
+        {
+            using (var client1 = new TestClient())
+            using (var client2 = new TestClient())
+            {
+                var output1 = Channel.CreateUnbounded<HubMessage>();
+                var output2 = Channel.CreateUnbounded<HubMessage>();
+
+                var manager = new DefaultHubLifetimeManager<MyHub>();
+                var connection1 = new HubConnectionContext(output1, client1.Connection);
+                var connection2 = new HubConnectionContext(output2, client2.Connection);
+
+                await manager.OnConnectedAsync(connection1);
+                await manager.OnConnectedAsync(connection2);
+
+                await manager.AddGroupAsync(connection1.ConnectionId, "gunit");
+
+                await manager.InvokeGroupAsync("gunit", "Hello", new object[] { "World" });
+
+                Assert.True(output1.In.TryRead(out var item));
+                var message = item as InvocationMessage;
+                Assert.NotNull(message);
+                Assert.Equal("Hello", message.Target);
+                Assert.Single(message.Arguments);
+                Assert.Equal("World", (string)message.Arguments[0]);
+
+                Assert.False(output2.In.TryRead(out item));
+            }
+        }
+
+        [Fact]
+        public async Task InvokeConnectionAsyncWritesToConnectionOutput()
+        {
+            using (var client = new TestClient())
+            {
+                var output = Channel.CreateUnbounded<HubMessage>();
+                var manager = new DefaultHubLifetimeManager<MyHub>();
+                var connection = new HubConnectionContext(output, client.Connection);
+
+                await manager.OnConnectedAsync(connection);
+
+                await manager.InvokeConnectionAsync(connection.ConnectionId, "Hello", new object[] { "World" });
+
+                Assert.True(output.In.TryRead(out var item));
+                var message = item as InvocationMessage;
+                Assert.NotNull(message);
+                Assert.Equal("Hello", message.Target);
+                Assert.Single(message.Arguments);
+                Assert.Equal("World", (string)message.Arguments[0]);
+            }
+        }
+
+        [Fact]
+        public async Task InvokeConnectionAsyncOnNonExistentConnectionNoops()
+        {
+            var manager = new DefaultHubLifetimeManager<MyHub>();
+            await manager.InvokeConnectionAsync("NotARealConnectionId", "Hello", new object[] { "World" });
+        }
+
+        [Fact]
+        public async Task AddGroupOnNonExistentConnectionNoops()
+        {
+            var manager = new DefaultHubLifetimeManager<MyHub>();
+            await manager.AddGroupAsync("NotARealConnectionId", "MyGroup");
+        }
+
+        [Fact]
+        public async Task RemoveGroupOnNonExistentConnectionNoops()
+        {
+            var manager = new DefaultHubLifetimeManager<MyHub>();
+            await manager.RemoveGroupAsync("NotARealConnectionId", "MyGroup");
+        }
+
+        private class MyHub : Hub
+        {
+
+        }
+    }
+}