Merge pull request #19910 from nextcloud/bugfix/noid/invalid-from-mail

Do not use the instance name as user part of from mail addresses

lib/private/Mail/Mailer.php

@@ -169,7 +169,7 @@ class Mailer implements IMailer {
 		$debugMode = $this->config->getSystemValue('mail_smtpdebug', false);
 
 		if (empty($message->getFrom())) {
-			$message->setFrom([\OCP\Util::getDefaultEmailAddress($this->defaults->getName()) => $this->defaults->getName()]);
+			$message->setFrom([\OCP\Util::getDefaultEmailAddress('no-reply') => $this->defaults->getName()]);
 		}
 
 		$failedRecipients = [];