diff --git a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcher.java b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcher.java
index 9e4cca6949..6f58df0332 100644
--- a/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcher.java
+++ b/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcher.java
@@ -88,7 +88,8 @@ public abstract class ApplicationContextServerWebExchangeMatcher<C>
 	@SuppressWarnings("unchecked")
 	private Supplier<C> createContext(ServerWebExchange exchange) {
 		ApplicationContext context = exchange.getApplicationContext();
-		Assert.state(context != null, "No ApplicationContext found.");
+		Assert.state(context != null,
+				"No ApplicationContext found on ServerWebExchange.");
 		if (this.contextClass.isInstance(context)) {
 			return () -> (C) context;
 		}
diff --git a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcherTests.java b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcherTests.java
index 7ed62f17d3..f436e86751 100644
--- a/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcherTests.java
+++ b/spring-boot-project/spring-boot/src/test/java/org/springframework/boot/security/reactive/ApplicationContextServerWebExchangeMatcherTests.java
@@ -91,7 +91,7 @@ public class ApplicationContextServerWebExchangeMatcherTests {
 		MockServerWebExchange exchange = MockServerWebExchange
 				.from(MockServerHttpRequest.get("/path").build());
 		this.thrown.expect(IllegalStateException.class);
-		this.thrown.expectMessage("No ApplicationContext found.");
+		this.thrown.expectMessage("No ApplicationContext found on ServerWebExchange.");
 		new TestApplicationContextServerWebExchangeMatcher<>(ExistingBean.class)
 				.callMatchesAndReturnProvidedContext(exchange);
 	}