diff --git a/lib/AccountManager/App.pm b/lib/AccountManager/App.pm
index 0f52e0dc96bc7830d20cf7d46350c41ba7ceb0f4..96e3c15475071d2519c476bb2e40bd9cc583f17d 100644
--- a/lib/AccountManager/App.pm
+++ b/lib/AccountManager/App.pm
@@ -496,6 +496,8 @@ sub req_complete_challenge {
         token     => $token->token(),
     };
 
+    binmode($handle, ":utf8");
+
     unless ($tt2->process($template, $data, $handle)) {
         $self->{logger}->errorf("Mail notification error: %s", $tt2->error());
         $self->respond(