diff --git a/Source/ARTRealtime.m b/Source/ARTRealtime.m
index f6e552133..ddb5f39ae 100644
--- a/Source/ARTRealtime.m
+++ b/Source/ARTRealtime.m
@@ -221,6 +221,20 @@ - (void)transition:(ARTRealtimeConnectionState)state withErrorInfo:(ARTErrorInfo
                 _transport.delegate = self;
                 [_transport connect];
             }
+
+            if (previousState == ARTRealtimeDisconnected) {
+                __GENERIC(NSArray, ARTQueuedMessage *) *pending = self.pendingMessages;
+                _pendingMessages = [[NSMutableArray alloc] init];
+                for (ARTQueuedMessage *queued in pending) {
+                    [self send:queued.msg callback:^(ARTStatus *__art_nonnull status) {
+                        for (id cb in queued.cbs) {
+                            ((void(^)(ARTStatus *__art_nonnull))cb)(status);
+                        }
+                    }];
+                }
+
+            }
+
             break;
         case ARTRealtimeConnected:
             [self cancelSuspendTimer];
diff --git a/Spec/RealtimeClientConnection.swift b/Spec/RealtimeClientConnection.swift
index a1fa8cd12..626266878 100644
--- a/Spec/RealtimeClientConnection.swift
+++ b/Spec/RealtimeClientConnection.swift
@@ -1701,6 +1701,43 @@ class RealtimeClientConnection: QuickSpec {
                 }
             }
 
+            context("Transport disconnected side effects") {
+
+                // RTN19a
+                it("should resend any ProtocolMessage that is awaiting a ACK/NACK") {
+                    let options = AblyTests.commonAppSetup()
+                    options.logLevel = .Debug
+                    options.disconnectedRetryTimeout = 0.1
+                    let client = AblyTests.newRealtime(options)
+                    defer { client.close() }
+                    let channel = client.channels.get("test")
+                    let transport = client.transport as! TestProxyTransport
+
+                    expect(client.connection.state).toEventually(equal(ARTRealtimeConnectionState.Connected), timeout: testTimeout)
+
+                    waitUntil(timeout: testTimeout) { done in
+                        channel.attach { _ in done() }
+                    }
+
+                    waitUntil(timeout: testTimeout) { done in
+                        transport.ignoreSends = true
+                        channel.publish(nil, data: "message") { error in
+                            expect(error).to(beNil())
+                            let newTransport = client.transport as! TestProxyTransport
+                            expect(transport.protocolMessagesReceived.filter{ $0.action == .Connected }).to(haveCount(1))
+                            expect(newTransport.protocolMessagesReceived.filter{ $0.action == .Connected }).to(haveCount(1))
+                            expect(transport.protocolMessagesSent.filter{ $0.action == .Message }).to(haveCount(0))
+                            expect(transport.protocolMessagesSentIgnored.filter{ $0.action == .Message }).to(haveCount(1))
+                            expect(newTransport.protocolMessagesSent.filter{ $0.action == .Message }).to(haveCount(1))
+                            done()
+                        }
+                        transport.ignoreSends = false
+                        client.onDisconnected()
+                    }
+                }
+
+            }
+
         }
     }
 }
diff --git a/Spec/TestUtilities.swift b/Spec/TestUtilities.swift
index ebec9063a..66c379857 100644
--- a/Spec/TestUtilities.swift
+++ b/Spec/TestUtilities.swift
@@ -492,6 +492,7 @@ class TestProxyTransport: ARTWebSocketTransport {
 
     private(set) var protocolMessagesSent = [ARTProtocolMessage]()
     private(set) var protocolMessagesReceived = [ARTProtocolMessage]()
+    private(set) var protocolMessagesSentIgnored = [ARTProtocolMessage]()
 
     private(set) var rawDataSent = [NSData]()
     private(set) var rawDataReceived = [NSData]()
@@ -502,6 +503,7 @@ class TestProxyTransport: ARTWebSocketTransport {
     var afterProcessingReceivedMessage: Optional<(ARTProtocolMessage)->()> = nil
 
     var actionsIgnored = [ARTProtocolMessageAction]()
+    var ignoreSends = false
 
     override func setupWebSocket(params: [NSURLQueryItem], withOptions options: ARTClientOptions, resumeKey: String?, connectionSerial: NSNumber?) -> NSURL {
         let url = super.setupWebSocket(params, withOptions: options, resumeKey: resumeKey, connectionSerial: connectionSerial)
@@ -510,6 +512,10 @@ class TestProxyTransport: ARTWebSocketTransport {
     }
 
     override func send(msg: ARTProtocolMessage) {
+        if ignoreSends {
+            protocolMessagesSentIgnored.append(msg)
+            return
+        }
         protocolMessagesSent.append(msg)
         if let performEvent = beforeProcessingSentMessage {
             performEvent(msg)