diff --git a/src/Util/EMailer/MailBuilder.php b/src/Util/EMailer/MailBuilder.php
index fe801bd562..c2c2f75dc5 100644
--- a/src/Util/EMailer/MailBuilder.php
+++ b/src/Util/EMailer/MailBuilder.php
@@ -140,14 +140,17 @@ abstract class MailBuilder
 	{
 		if ((empty($this->recipientAddress)) &&
 		    !empty($this->recipientUid)) {
-			$user = User::getById($this->recipientUid, ['username', 'email']);
+			$user = User::getById($this->recipientUid, ['email']);
 
 			if (!empty($user)) {
-				$this->senderName    = $user['username'];
-				$this->senderAddress = $user['email'];
+				$this->recipientAddress = $user['email'];
 			}
 		}
 
+		if (empty($this->recipientAddress)) {
+			throw new InternalServerErrorException('Recipient address is missing.');
+		}
+
 		if (empty($this->senderAddress) || empty($this->senderName)) {
 			throw new InternalServerErrorException('Sender address or name is missing.');
 		}