From e52a8f0941fd53c9b087e6e59a7018d11af72dff Mon Sep 17 00:00:00 2001
From: Amaury Martiny <amaury.martiny@protonmail.com>
Date: Sat, 23 May 2020 12:02:06 +0200
Subject: [PATCH] fix: Add additional error check for undeliverable (#374)

---
 core/src/smtp.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/core/src/smtp.rs b/core/src/smtp.rs
index 05841b678..ad1315c56 100644
--- a/core/src/smtp.rs
+++ b/core/src/smtp.rs
@@ -246,6 +246,8 @@ async fn email_deliverable(
 				// 550 5.1.1 No such user - pp
 				// 550 No such user here
 				|| err_string.contains("no such user")
+				// 4.2.1 The user you are trying to contact is receiving mail at a rate...
+				|| err_string.contains("is receiving mail at a rate")
 				// 550 5.1.1 : Mailbox not found
 				// 550 Unknown address error ‘MAILBOX NOT FOUND’
 				|| err_string.contains("not found")