diff --git a/src/runtime/setup.rs b/src/runtime/setup.rs
index 3e35d1aead0774491e75544ac3440cef14ff8271..701228314b31045c8fbdd3db4187345179253120 100644
--- a/src/runtime/setup.rs
+++ b/src/runtime/setup.rs
@@ -327,7 +327,7 @@ fn setup_endpoints_and_pair_ports(
             log!(logger, "Net endpoint {} beginning setup with {:?}", index, &endpoint_setup);
             let todo_endpoint = if let EndpointPolarity::Active = endpoint_setup.endpoint_polarity {
                 let mut stream = TcpStream::connect(endpoint_setup.sock_addr)
-                    .expect("mio::TcpStream connect should not fail!");
+                    .map_err(|_| Ce::TcpInvalidConnect(endpoint_setup.sock_addr))?;
                 poll.registry().register(&mut stream, token, BOTH).unwrap();
                 NetTodoEndpoint::PeerInfoRecving(NetEndpoint { stream, inbox: vec![] })
             } else {