diff --git a/src/Mail/EngelsystemMailer.php b/src/Mail/EngelsystemMailer.php
index 36cd33af..fe6e9f8b 100644
--- a/src/Mail/EngelsystemMailer.php
+++ b/src/Mail/EngelsystemMailer.php
@@ -98,7 +98,7 @@ class EngelsystemMailer extends Mailer
     public function send($to, string $subject, string $body): int
     {
         if ($this->subjectPrefix) {
-            $subject = sprintf('[%s] %s', $this->subjectPrefix, $subject);
+            $subject = sprintf('[%s] %s', $this->subjectPrefix, trim($subject));
         }
 
         return parent::send($to, $subject, $body);
diff --git a/tests/Unit/Mail/EngelsystemMailerTest.php b/tests/Unit/Mail/EngelsystemMailerTest.php
index 8d649004..6a3642e5 100644
--- a/tests/Unit/Mail/EngelsystemMailerTest.php
+++ b/tests/Unit/Mail/EngelsystemMailerTest.php
@@ -108,7 +108,7 @@ class EngelsystemMailerTest extends TestCase
 
         $this->assertEquals('Mail test', $mailer->getSubjectPrefix());
 
-        $return = $mailer->send('to@xam.pel', 'Foo Bar', 'Lorem Ipsum!');
+        $return = $mailer->send('to@xam.pel', 'Foo Bar ', 'Lorem Ipsum!');
         $this->assertEquals(1, $return);
     }
 }