diff --git a/spring-graphql/src/main/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandler.java b/spring-graphql/src/main/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandler.java
index c983e5a39..0b0798dda 100644
--- a/spring-graphql/src/main/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandler.java
+++ b/spring-graphql/src/main/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandler.java
@@ -246,7 +246,10 @@ private Flux<WebSocketMessage> handleWebOutput(WebSocketSession session, String
 								.message(ex.getMessage())
 								.build()
 								.toSpecification();
-						return Mono.just(encode(session, id, MessageType.ERROR, errorMap));
+
+						// Payload needs to be an array
+						//  see: https://github.com/enisdenjo/graphql-ws/blob/master/docs/interfaces/common.ErrorMessage.md#payload
+						return Mono.just(encode(session, id, MessageType.ERROR, Collections.singletonList(errorMap)));
 				});
 	}
 
diff --git a/spring-graphql/src/main/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandler.java b/spring-graphql/src/main/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandler.java
index caaafe19d..ca7254a0e 100644
--- a/spring-graphql/src/main/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandler.java
+++ b/spring-graphql/src/main/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandler.java
@@ -260,7 +260,10 @@ private Flux<TextMessage> handleWebOutput(WebSocketSession session, String id, W
 						String message = ex.getMessage();
 						Map<String, Object> errorMap = GraphqlErrorBuilder.newError().errorType(errorType).message(message).build()
 								.toSpecification();
-						return Mono.just(encode(id, MessageType.ERROR, errorMap));
+
+						// Payload needs to be an array
+						//  see: https://github.com/enisdenjo/graphql-ws/blob/master/docs/interfaces/common.ErrorMessage.md#payload
+						return Mono.just(encode(id, MessageType.ERROR, Collections.singletonList(errorMap)));
 				});
 	}
 
diff --git a/spring-graphql/src/test/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandlerTests.java b/spring-graphql/src/test/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandlerTests.java
index c6a6340bf..5bfc3e939 100644
--- a/spring-graphql/src/test/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandlerTests.java
+++ b/spring-graphql/src/test/java/org/springframework/graphql/web/webflux/GraphQlWebSocketHandlerTests.java
@@ -26,6 +26,8 @@
 
 import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
+import org.springframework.graphql.GraphQlSetup;
+import org.springframework.graphql.web.WebGraphQlHandler;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.core.publisher.Sinks;
@@ -245,6 +247,60 @@ void clientCompletion() {
 				.verifyTimeout(Duration.ofMillis(500));
 	}
 
+	@Test
+	void errorMessagePayloadIsCorrectArray() {
+		final String GREETING_QUERY = "{" +
+				"\"id\":\"" + SUBSCRIPTION_ID + "\"," +
+				"\"type\":\"subscribe\"," +
+				"\"payload\":{\"query\": \"" +
+				"  subscription TestTypenameSubscription {" +
+				"    greeting" +
+				"  }\"}" +
+				"}";
+
+		WebGraphQlHandler initHandler = GraphQlSetup.schemaContent("" +
+						"type Subscription { greeting: String! }" +
+						"type Query { greetingUnused: String! }")
+				.subscriptionFetcher("greeting", env -> Flux.just("a", null, "b"))
+				.webInterceptor()
+				.toWebGraphQlHandler();
+
+		GraphQlWebSocketHandler handler = new GraphQlWebSocketHandler(
+				initHandler,
+				ServerCodecConfigurer.create(),
+				Duration.ofSeconds(60));
+
+		TestWebSocketSession session = new TestWebSocketSession(Flux.just(
+				toWebSocketMessage("{\"type\":\"connection_init\"}"),
+				toWebSocketMessage(GREETING_QUERY)));
+		handler.handle(session).block();
+
+		StepVerifier.create(session.getOutput())
+				.consumeNextWith((message) -> assertMessageType(message, "connection_ack"))
+				.consumeNextWith((message) -> assertThat(decode(message))
+						.hasSize(3)
+						.containsEntry("id", SUBSCRIPTION_ID)
+						.containsEntry("type", "next")
+						.extractingByKey("payload", as(InstanceOfAssertFactories.map(String.class, Object.class)))
+						.extractingByKey("data", as(InstanceOfAssertFactories.map(String.class, Object.class)))
+						.containsEntry("greeting", "a"))
+				.consumeNextWith((message) -> assertThat(decode(message))
+						.hasSize(3)
+						.containsEntry("id", SUBSCRIPTION_ID)
+						.containsEntry("type", "error")
+						.hasEntrySatisfying("payload", payload -> assertThat(payload)
+								.asList()
+								.hasSize(1)
+								.allSatisfy(theError -> assertThat(theError)
+										.asInstanceOf(InstanceOfAssertFactories.map(String.class, Object.class))
+										.hasSize(3)
+										.hasEntrySatisfying("locations", loc -> assertThat(loc).asList().isEmpty())
+										.hasEntrySatisfying("message", msg -> assertThat(msg).asString().contains("null"))
+										.extractingByKey("extensions", as(InstanceOfAssertFactories.map(String.class, Object.class)))
+										.containsEntry("classification", "DataFetchingException"))))
+				.verifyComplete();
+	}
+
 	private TestWebSocketSession handle(Flux<WebSocketMessage> input, WebInterceptor... interceptors) {
 		GraphQlWebSocketHandler handler = new GraphQlWebSocketHandler(
 				initHandler(interceptors),
diff --git a/spring-graphql/src/test/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandlerTests.java b/spring-graphql/src/test/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandlerTests.java
index 52d1701e0..fbdc57f13 100644
--- a/spring-graphql/src/test/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandlerTests.java
+++ b/spring-graphql/src/test/java/org/springframework/graphql/web/webmvc/GraphQlWebSocketHandlerTests.java
@@ -29,6 +29,9 @@
 
 import org.assertj.core.api.InstanceOfAssertFactories;
 import org.junit.jupiter.api.Test;
+import org.springframework.graphql.GraphQlSetup;
+import org.springframework.graphql.web.WebGraphQlHandler;
+import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 
@@ -249,6 +252,57 @@ void clientCompletion() throws Exception {
 				.verifyTimeout(Duration.ofMillis(500));
 	}
 
+	@Test
+	void errorMessagePayloadIsCorrectArray() throws Exception {
+		final String GREETING_QUERY = "{" +
+				"\"id\":\"" + SUBSCRIPTION_ID + "\"," +
+				"\"type\":\"subscribe\"," +
+				"\"payload\":{\"query\": \"" +
+				"  subscription TestTypenameSubscription {" +
+				"    greeting" +
+				"  }\"}" +
+				"}";
+
+		WebGraphQlHandler initHandler = GraphQlSetup.schemaContent("" +
+						"type Subscription { greeting: String! }" +
+						"type Query { greetingUnused: String! }")
+				.subscriptionFetcher("greeting", env -> Flux.just("a", null, "b"))
+				.webInterceptor()
+				.toWebGraphQlHandler();
+
+		GraphQlWebSocketHandler handler = new GraphQlWebSocketHandler(initHandler, converter, Duration.ofSeconds(60));
+
+		handle(handler,
+				new TextMessage("{\"type\":\"connection_init\"}"),
+				new TextMessage(GREETING_QUERY));
+
+		StepVerifier.create(this.session.getOutput())
+				.consumeNextWith((message) -> assertMessageType(message, "connection_ack"))
+				.consumeNextWith((message) -> assertThat(decode(message))
+						.hasSize(3)
+						.containsEntry("id", SUBSCRIPTION_ID)
+						.containsEntry("type", "next")
+						.extractingByKey("payload", as(InstanceOfAssertFactories.map(String.class, Object.class)))
+						.extractingByKey("data", as(InstanceOfAssertFactories.map(String.class, Object.class)))
+						.containsEntry("greeting", "a"))
+				.consumeNextWith((message) -> assertThat(decode(message))
+						.hasSize(3)
+						.containsEntry("id", SUBSCRIPTION_ID)
+						.containsEntry("type", "error")
+						.hasEntrySatisfying("payload", payload -> assertThat(payload)
+								.asList()
+								.hasSize(1)
+								.allSatisfy(theError -> assertThat(theError)
+										.asInstanceOf(InstanceOfAssertFactories.map(String.class, Object.class))
+										.hasSize(3)
+										.hasEntrySatisfying("locations", loc -> assertThat(loc).asList().isEmpty())
+										.hasEntrySatisfying("message", msg -> assertThat(msg).asString().contains("null"))
+										.extractingByKey("extensions", as(InstanceOfAssertFactories.map(String.class, Object.class)))
+										.containsEntry("classification", "DataFetchingException"))))
+				.then(this.session::close)
+				.verifyComplete();
+	}
+
 	private void handle(GraphQlWebSocketHandler handler, TextMessage... textMessages) throws Exception {
 		handler.afterConnectionEstablished(this.session);
 		for (TextMessage message : textMessages) {