diff --git a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/BearerTokenAuthenticationFilter.java b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/BearerTokenAuthenticationFilter.java
index 6eb2778815c..f34d153c9b3 100644
--- a/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/BearerTokenAuthenticationFilter.java
+++ b/oauth2/oauth2-resource-server/src/main/java/org/springframework/security/oauth2/server/resource/web/BearerTokenAuthenticationFilter.java
@@ -132,7 +132,7 @@ protected void doFilterInternal(HttpServletRequest request, HttpServletResponse
 			SecurityContextHolder.clearContext();
 
 			if (debug) {
-				this.logger.debug("Authentication request for failed: " + failed);
+				this.logger.debug("Authentication request for failed!", failed);
 			}
 
 			this.authenticationFailureHandler.onAuthenticationFailure(request, response, failed);