diff --git a/src/lib.rs b/src/lib.rs
index 274ec3a..8db0fd7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -202,4 +202,12 @@ mod tests {
         );
         assert_eq!("text/html", resp.content_type());
     }
+
+    #[test]
+    #[cfg(feature = "tls")]
+    fn connect_https_invalid_name() {
+        let resp = get("https://example.com{REQUEST_URI}/").call();
+        assert_eq!(400, resp.status());
+        assert!(resp.synthetic());
+    }
 }
diff --git a/src/stream.rs b/src/stream.rs
index a6b0d45..b4bf0e2 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -156,7 +156,8 @@ pub(crate) fn connect_https(unit: &Unit) -> Result<Stream, Error> {
     let hostname = unit.url.host_str().unwrap();
     let port = unit.url.port().unwrap_or(443);
 
-    let sni = webpki::DNSNameRef::try_from_ascii_str(hostname).unwrap();
+    let sni = webpki::DNSNameRef::try_from_ascii_str(hostname)
+        .map_err(|err| Error::DnsFailed(err.to_string()))?;
     let sess = rustls::ClientSession::new(&*TLS_CONF, sni);
 
     let sock = connect_host(unit, hostname, port)?;