diff --git a/core/invitation.go b/core/invitation.go
index 2822b6a..7e2948c 100644
--- a/core/invitation.go
+++ b/core/invitation.go
@@ -163,29 +163,22 @@ func (iv *invitation) AcceptInvitation(ctx wshandler.ApiCallContext) {
 		Timestamp: now,
 	}
 
-	// 나한테 상대방을 친구로 만들고
-	if err := iv.f.addFriend(&f1); err == nil {
-		iv.wsh.SendUpstreamMessage(&wshandler.UpstreamMessage{
-			Target: f1.From.Hex(),
-			Body:   []friendDoc{f1},
-			Tag:    friends_tag,
-		})
-	} else {
-		logger.Println("AcceptInvitation failed. addFriend(f1) err :", err)
-		return
-	}
+	// 나한테 상대방을 친구로 만든다
+	// SendUpstreamMessage를 먼저 해야 함
+	iv.wsh.SendUpstreamMessage(&wshandler.UpstreamMessage{
+		Target: f1.From.Hex(),
+		Body:   []friendDoc{f1},
+		Tag:    friends_tag,
+	})
+	iv.f.addFriend(&f1)
 
 	// 상대방한테 나를 친구로 만듬
-	if err := iv.f.addFriend(&f2); err == nil {
-		iv.wsh.SendUpstreamMessage(&wshandler.UpstreamMessage{
-			Target: f2.From.Hex(),
-			Body:   []friendDoc{f2},
-			Tag:    friends_tag,
-		})
-	} else {
-		logger.Println("AcceptInvitation failed. addFriend(f2) err :", err)
-		return
-	}
+	iv.wsh.SendUpstreamMessage(&wshandler.UpstreamMessage{
+		Target: f2.From.Hex(),
+		Body:   []friendDoc{f2},
+		Tag:    friends_tag,
+	})
+	iv.f.addFriend(&f2)
 
 	iv.mongoClient.Delete(invitation_collection_name, bson.M{"_id": invId})
 }