diff --git a/config/src/test/java/org/springframework/security/config/annotation/web/configurers/oauth2/server/resource/OAuth2ResourceServerConfigurerTests.java b/config/src/test/java/org/springframework/security/config/annotation/web/configurers/oauth2/server/resource/OAuth2ResourceServerConfigurerTests.java
index 8914c8e260..b516954f8e 100644
--- a/config/src/test/java/org/springframework/security/config/annotation/web/configurers/oauth2/server/resource/OAuth2ResourceServerConfigurerTests.java
+++ b/config/src/test/java/org/springframework/security/config/annotation/web/configurers/oauth2/server/resource/OAuth2ResourceServerConfigurerTests.java
@@ -1127,7 +1127,7 @@ public class OAuth2ResourceServerConfigurerTests {
 				.with(bearerToken("token")))
 				.andExpect(status().isUnauthorized())
 				.andExpect(header().string(HttpHeaders.WWW_AUTHENTICATE,
-						containsString("Provided token [token] isn't active")));
+						containsString("Provided token isn't active")));
 	}
 
 	@Test
diff --git a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospector.java b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospector.java
index c4b0569ada..642dc451f1 100644
--- a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospector.java
+++ b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospector.java
@@ -133,7 +133,7 @@ public class NimbusOpaqueTokenIntrospector implements OpaqueTokenIntrospector {
 	public OAuth2AuthenticatedPrincipal introspect(String token) {
 		RequestEntity<?> requestEntity = this.requestEntityConverter.convert(token);
 		if (requestEntity == null) {
-			throw new OAuth2IntrospectionException("Provided token [" + token + "] isn't active");
+			throw new OAuth2IntrospectionException("requestEntityConverter returned a null entity");
 		}
 
 		ResponseEntity<String> responseEntity = makeRequest(requestEntity);
@@ -143,7 +143,7 @@ public class NimbusOpaqueTokenIntrospector implements OpaqueTokenIntrospector {
 
 		// relying solely on the authorization server to validate this token (not checking 'exp', for example)
 		if (!introspectionSuccessResponse.isActive()) {
-			throw new OAuth2IntrospectionException("Provided token [" + token + "] isn't active");
+			throw new OAuth2IntrospectionException("Provided token isn't active");
 		}
 
 		return convertClaimsSet(introspectionSuccessResponse);
diff --git a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospector.java b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospector.java
index 9908979d28..91690f8f10 100644
--- a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospector.java
+++ b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospector.java
@@ -154,7 +154,7 @@ public class NimbusReactiveOpaqueTokenIntrospector implements ReactiveOpaqueToke
 	private void validate(String token, TokenIntrospectionSuccessResponse response) {
 		// relying solely on the authorization server to validate this token (not checking 'exp', for example)
 		if (!response.isActive()) {
-			throw new OAuth2IntrospectionException("Provided token [" + token + "] isn't active");
+			throw new OAuth2IntrospectionException("Provided token isn't active");
 		}
 	}
 
diff --git a/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospectorTests.java b/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospectorTests.java
index 966d8eae62..2ebf11c8b5 100644
--- a/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospectorTests.java
+++ b/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusOpaqueTokenIntrospectorTests.java
@@ -168,7 +168,7 @@ public class NimbusOpaqueTokenIntrospectorTests {
 		assertThatCode(() -> introspectionClient.introspect("token"))
 				.isInstanceOf(OAuth2IntrospectionException.class)
 				.extracting("message")
-				.containsExactly("Provided token [token] isn't active");
+				.containsExactly("Provided token isn't active");
 	}
 
 	@Test
diff --git a/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospectorTests.java b/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospectorTests.java
index 0b58f45e6b..7454debbaf 100644
--- a/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospectorTests.java
+++ b/oauth2/oauth2-resource-server/src/test/java/org/springframework/security/oauth2/server/resource/introspection/NimbusReactiveOpaqueTokenIntrospectorTests.java
@@ -142,7 +142,7 @@ public class NimbusReactiveOpaqueTokenIntrospectorTests {
 		assertThatCode(() -> introspectionClient.introspect("token").block())
 				.isInstanceOf(OAuth2IntrospectionException.class)
 				.extracting("message")
-				.containsExactly("Provided token [token] isn't active");
+				.containsExactly("Provided token isn't active");
 	}
 
 	@Test