X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FUtil%2FEmailer.php;h=8116fbf85017d646e03969a87e409aaee96d292c;hb=bdb5aa6bd92528da480baab99ca92a3768a89d0b;hp=b402abf25e66ca01230ebe3bf286ea58ce8e7aa3;hpb=545517e85f9ae5c27334b16d6e9cedecc41063ed;p=friendica.git

diff --git a/src/Util/Emailer.php b/src/Util/Emailer.php
index b402abf25e..8116fbf850 100644
--- a/src/Util/Emailer.php
+++ b/src/Util/Emailer.php
@@ -1,6 +1,6 @@
 <?php
 /**
- * @copyright Copyright (C) 2020, Friendica
+ * @copyright Copyright (C) 2010-2021, the Friendica project
  *
  * @license GNU AGPL version 3 or any later version
  *
@@ -134,6 +134,17 @@ class Emailer
 			return true;
 		}
 
+		// @see https://github.com/friendica/friendica/issues/9142
+		$countMessageId = 0;
+		foreach ($email->getAdditionalMailHeader() as $name => $value) {
+			if (strtolower($name) == 'message-id') {
+				$countMessageId += count($value);
+			}
+		}
+		if ($countMessageId > 0) {
+			$this->logger->warning('More than one Message-ID found - RFC violation', ['email' => $email]);
+		}
+
 		$email_textonly = false;
 		if (!empty($email->getRecipientUid())) {
 			$email_textonly = $this->pConfig->get($email->getRecipientUid(), 'system', 'email_textonly');