diff --git a/rust/gateway/src/eventloop.rs b/rust/gateway/src/eventloop.rs
index fb4e29848..86e5559ed 100644
--- a/rust/gateway/src/eventloop.rs
+++ b/rust/gateway/src/eventloop.rs
@@ -652,6 +652,16 @@ async fn phoenix_channel_event_loop(
                     break;
                 }
             }
+            Either::Left((
+                Ok(phoenix_channel::Event::ErrorResponse {
+                    topic,
+                    res: phoenix_channel::ErrorReply::UnmatchedTopic,
+                    ..
+                }),
+                _,
+            )) => {
+                portal.join(topic, ());
+            }
             Either::Left((Ok(phoenix_channel::Event::ErrorResponse { topic, req_id, res }), _)) => {
                 tracing::warn!(%topic, %req_id, "Request failed: {res:?}");
             }