diff --git a/src/server.tsx b/src/server.tsx
index f2780e0..ba4fbec 100644
--- a/src/server.tsx
+++ b/src/server.tsx
@@ -167,7 +167,7 @@ app.get("/", c => c.html(<Layout><Terminal /></Layout>))
 app.get("/ws", c => {
     const _sessionId = c.req.query("session")
     const url = new URL(c.req.url)
-    let hostname = url.hostname + (url.port === "80" ? "" : `:${url.port}`)
+    let hostname = url.hostname + (!url.port || url.port === "80" ? "" : `:${url.port}`)
 
     return upgradeWebSocket(c, {
         async onOpen(_e, ws) {