diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnection.java b/service/src/main/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnection.java
index 4b153fd50..88c76ed2c 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnection.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnection.java
@@ -88,6 +88,8 @@ public class WebSocketConnection implements MessageAvailabilityListener, Displac
   private static final long RETRY_DELAY_MILLIS = 1_000;
   private static final int RETRY_DELAY_JITTER_MILLIS = 500;
 
+  private static final int DEFAULT_SEND_FUTURES_TIMEOUT_MILLIS = 5 * 60 * 1000;
+
   private static final Logger logger = LoggerFactory.getLogger(WebSocketConnection.class);
 
   private final ReceiptSender receiptSender;
@@ -96,6 +98,9 @@ public class WebSocketConnection implements MessageAvailabilityListener, Displac
   private final AuthenticatedAccount auth;
   private final Device device;
   private final WebSocketClient client;
+
+  private final int sendFuturesTimeoutMillis;
+
   private final ScheduledExecutorService retrySchedulingExecutor;
 
   private final boolean isDesktopClient;
@@ -123,11 +128,31 @@ public class WebSocketConnection implements MessageAvailabilityListener, Displac
       Device device,
       WebSocketClient client,
       ScheduledExecutorService retrySchedulingExecutor) {
+
+    this(receiptSender,
+        messagesManager,
+        auth,
+        device,
+        client,
+        DEFAULT_SEND_FUTURES_TIMEOUT_MILLIS,
+        retrySchedulingExecutor);
+  }
+
+  @VisibleForTesting
+  WebSocketConnection(ReceiptSender receiptSender,
+      MessagesManager messagesManager,
+      AuthenticatedAccount auth,
+      Device device,
+      WebSocketClient client,
+      int sendFuturesTimeoutMillis,
+      ScheduledExecutorService retrySchedulingExecutor) {
+
     this.receiptSender = receiptSender;
     this.messagesManager = messagesManager;
     this.auth = auth;
     this.device = device;
     this.client = client;
+    this.sendFuturesTimeoutMillis = sendFuturesTimeoutMillis;
     this.retrySchedulingExecutor = retrySchedulingExecutor;
 
     Optional<ClientPlatform> maybePlatform;
@@ -329,17 +354,20 @@ public class WebSocketConnection implements MessageAvailabilityListener, Displac
         }
       }
 
-      CompletableFuture.allOf(sendFutures).whenComplete((v, cause) -> {
-        if (cause == null) {
-          if (messages.hasMore()) {
-            sendNextMessagePage(cachedMessagesOnly, queueClearedFuture);
-          } else {
-            queueClearedFuture.complete(null);
-          }
-        } else {
-          queueClearedFuture.completeExceptionally(cause);
-        }
-      });
+      // Set a large, non-zero timeout, to prevent any failure to acknowledge receipt from blocking indefinitely
+      CompletableFuture.allOf(sendFutures)
+          .orTimeout(sendFuturesTimeoutMillis, TimeUnit.MILLISECONDS)
+          .whenComplete((v, cause) -> {
+            if (cause == null) {
+              if (messages.hasMore()) {
+                sendNextMessagePage(cachedMessagesOnly, queueClearedFuture);
+              } else {
+                queueClearedFuture.complete(null);
+              }
+            } else {
+              queueClearedFuture.completeExceptionally(cause);
+            }
+          });
     } catch (final Exception e) {
       queueClearedFuture.completeExceptionally(e);
     }
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionIntegrationTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionIntegrationTest.java
index a505c5fbe..08b5de92a 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionIntegrationTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/websocket/WebSocketConnectionIntegrationTest.java
@@ -66,6 +66,8 @@ class WebSocketConnectionIntegrationTest {
   @RegisterExtension
   static final RedisClusterExtension REDIS_CLUSTER_EXTENSION = RedisClusterExtension.builder().build();
 
+  private static final int SEND_FUTURES_TIMEOUT_MILLIS = 100;
+
   private ExecutorService executorService;
   private MessagesDynamoDb messagesDynamoDb;
   private MessagesCache messagesCache;
@@ -102,6 +104,7 @@ class WebSocketConnectionIntegrationTest {
         new AuthenticatedAccount(() -> new Pair<>(account, device)),
         device,
         webSocketClient,
+        SEND_FUTURES_TIMEOUT_MILLIS,
         retrySchedulingExecutor);
   }