diff --git a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultAuthorizationCodeTokenResponseClientTests.java b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultAuthorizationCodeTokenResponseClientTests.java
index b26a53aa92..6751138cd3 100644
--- a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultAuthorizationCodeTokenResponseClientTests.java
+++ b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultAuthorizationCodeTokenResponseClientTests.java
@@ -15,12 +15,15 @@
  */
 package org.springframework.security.oauth2.client.endpoint;
 
+import java.time.Instant;
+
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
 import okhttp3.mockwebserver.RecordedRequest;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -34,8 +37,6 @@ import org.springframework.security.oauth2.core.endpoint.OAuth2AuthorizationExch
 import org.springframework.security.oauth2.core.endpoint.OAuth2AuthorizationRequest;
 import org.springframework.security.oauth2.core.endpoint.OAuth2AuthorizationResponse;
 
-import java.time.Instant;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
@@ -280,7 +281,7 @@ public class DefaultAuthorizationCodeTokenResponseClientTests {
 
 		assertThatThrownBy(() -> this.tokenResponseClient.getTokenResponse(this.authorizationCodeGrantRequest()))
 				.isInstanceOf(OAuth2AuthorizationException.class)
-				.hasMessage("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response: 500 Server Error");
+				.hasMessageContaining("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response");
 	}
 
 	private OAuth2AuthorizationCodeGrantRequest authorizationCodeGrantRequest() {
diff --git a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultClientCredentialsTokenResponseClientTests.java b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultClientCredentialsTokenResponseClientTests.java
index 1a2f93a31e..b24de2720b 100644
--- a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultClientCredentialsTokenResponseClientTests.java
+++ b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultClientCredentialsTokenResponseClientTests.java
@@ -15,12 +15,15 @@
  */
 package org.springframework.security.oauth2.client.endpoint;
 
+import java.time.Instant;
+
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
 import okhttp3.mockwebserver.RecordedRequest;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -31,8 +34,6 @@ import org.springframework.security.oauth2.core.OAuth2AccessToken;
 import org.springframework.security.oauth2.core.OAuth2AuthorizationException;
 import org.springframework.security.oauth2.core.endpoint.OAuth2AccessTokenResponse;
 
-import java.time.Instant;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
@@ -296,7 +297,7 @@ public class DefaultClientCredentialsTokenResponseClientTests {
 
 		assertThatThrownBy(() -> this.tokenResponseClient.getTokenResponse(clientCredentialsGrantRequest))
 				.isInstanceOf(OAuth2AuthorizationException.class)
-				.hasMessage("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response: 500 Server Error");
+				.hasMessageContaining("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response");
 	}
 
 	private MockResponse jsonResponse(String json) {
diff --git a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultPasswordTokenResponseClientTests.java b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultPasswordTokenResponseClientTests.java
index a1679455bb..6390ae3959 100644
--- a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultPasswordTokenResponseClientTests.java
+++ b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultPasswordTokenResponseClientTests.java
@@ -15,12 +15,15 @@
  */
 package org.springframework.security.oauth2.client.endpoint;
 
+import java.time.Instant;
+
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
 import okhttp3.mockwebserver.RecordedRequest;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -32,8 +35,6 @@ import org.springframework.security.oauth2.core.OAuth2AccessToken;
 import org.springframework.security.oauth2.core.OAuth2AuthorizationException;
 import org.springframework.security.oauth2.core.endpoint.OAuth2AccessTokenResponse;
 
-import java.time.Instant;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
@@ -209,7 +210,7 @@ public class DefaultPasswordTokenResponseClientTests {
 
 		assertThatThrownBy(() -> this.tokenResponseClient.getTokenResponse(passwordGrantRequest))
 				.isInstanceOf(OAuth2AuthorizationException.class)
-				.hasMessage("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response: 500 Server Error");
+				.hasMessageContaining("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response");
 	}
 
 	private MockResponse jsonResponse(String json) {
diff --git a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultRefreshTokenTokenResponseClientTests.java b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultRefreshTokenTokenResponseClientTests.java
index 5902eb4543..44c455a944 100644
--- a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultRefreshTokenTokenResponseClientTests.java
+++ b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/endpoint/DefaultRefreshTokenTokenResponseClientTests.java
@@ -15,12 +15,16 @@
  */
 package org.springframework.security.oauth2.client.endpoint;
 
+import java.time.Instant;
+import java.util.Collections;
+
 import okhttp3.mockwebserver.MockResponse;
 import okhttp3.mockwebserver.MockWebServer;
 import okhttp3.mockwebserver.RecordedRequest;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
@@ -34,9 +38,6 @@ import org.springframework.security.oauth2.core.TestOAuth2AccessTokens;
 import org.springframework.security.oauth2.core.TestOAuth2RefreshTokens;
 import org.springframework.security.oauth2.core.endpoint.OAuth2AccessTokenResponse;
 
-import java.time.Instant;
-import java.util.Collections;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
@@ -210,7 +211,7 @@ public class DefaultRefreshTokenTokenResponseClientTests {
 
 		assertThatThrownBy(() -> this.tokenResponseClient.getTokenResponse(refreshTokenGrantRequest))
 				.isInstanceOf(OAuth2AuthorizationException.class)
-				.hasMessage("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response: 500 Server Error");
+				.hasMessageContaining("[invalid_token_response] An error occurred while attempting to retrieve the OAuth 2.0 Access Token Response");
 	}
 
 	private MockResponse jsonResponse(String json) {