diff --git a/CHANGES.md b/CHANGES.md
index 387c7eada3fda061a75571df356d9e6e1e71c6b3..fea05af65a88ecc974e102aa4806ceacac5cd53c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -70,6 +70,7 @@ Release Notes.
 * Log collecting and query implementation
 * Support Alarm to feishu
 * Add the implementation of ConfigurationDiscovery on the OAP side.
+* Fix bug in `parseInternalErrorCode` where some error codes are never reached.
 
 #### UI
 * Fix un-removed tags in trace query.
diff --git a/oap-server/server-receiver-plugin/envoy-metrics-receiver-plugin/src/main/java/org/apache/skywalking/oap/server/receiver/envoy/als/LogEntry2MetricsAdapter.java b/oap-server/server-receiver-plugin/envoy-metrics-receiver-plugin/src/main/java/org/apache/skywalking/oap/server/receiver/envoy/als/LogEntry2MetricsAdapter.java
index ba9c69dc3fd1df61bac9bc29a9659daa8cc3a3c9..0317d77954e84d93e8d1fc3587cd3d99c1443931 100644
--- a/oap-server/server-receiver-plugin/envoy-metrics-receiver-plugin/src/main/java/org/apache/skywalking/oap/server/receiver/envoy/als/LogEntry2MetricsAdapter.java
+++ b/oap-server/server-receiver-plugin/envoy-metrics-receiver-plugin/src/main/java/org/apache/skywalking/oap/server/receiver/envoy/als/LogEntry2MetricsAdapter.java
@@ -202,7 +202,7 @@ public class LogEntry2MetricsAdapter {
                 return "fault_injected";
             } else if (responseFlags.getRateLimited()) {
                 return "rate_limited";
-            } else if (responseFlags.getUnauthorizedDetails() != null) {
+            } else if (responseFlags.hasUnauthorizedDetails()) {
                 return "unauthorized_details";
             } else if (responseFlags.getRateLimitServiceError()) {
                 return "rate_limit_service_error";