diff --git a/server/internal/apierr/apierr.go b/server/internal/apierr/apierr.go
index 5bae0cf..1b8b4d2 100644
--- a/server/internal/apierr/apierr.go
+++ b/server/internal/apierr/apierr.go
@@ -106,9 +106,8 @@ var (
 	}
 )
 
-// Webhook-specific errors.
+// Usage / ad errors.
 var (
-	// Usage / ads / quota errors.
 	ErrAdNotUnlocked = &Error{
 		Code:      "AD_NOT_UNLOCKED",
 		MessageZH: "请先观看激励视频解锁当日时长",
@@ -129,8 +128,10 @@ var (
 		MessageZH: "该广告回执已被使用",
 		MessageEn: "This ad receipt has already been used",
 	}
+)
 
-	// Webhook-specific errors.
+// Webhook-specific errors.
+var (
 	ErrWebhookSignature = &Error{
 		Code:      "WEBHOOK_INVALID_SIGNATURE",
 		MessageZH: "签名校验失败",