diff --git a/tokio-xmpp/src/starttls.rs b/tokio-xmpp/src/starttls.rs
index 77d0c8aa..c27caf0a 100644
--- a/tokio-xmpp/src/starttls.rs
+++ b/tokio-xmpp/src/starttls.rs
@@ -41,7 +41,7 @@ async fn get_tls_stream<S: AsyncRead + AsyncWrite + Unpin>(
 async fn get_tls_stream<S: AsyncRead + AsyncWrite + Unpin>(
     xmpp_stream: XMPPStream<S>,
 ) -> Result<TlsStream<S>, Error> {
-    let domain = format!("{}", xmpp_stream.jid.domain().to_owned());
+    let domain = xmpp_stream.jid.domain_str().to_owned();
     let domain = ServerName::try_from(domain.as_str())?;
     let stream = xmpp_stream.into_inner();
     let mut root_store = RootCertStore::empty();