diff --git a/src/platform.ts b/src/platform.ts
index b4c0fea7ba..e2fb5b8150 100644
--- a/src/platform.ts
+++ b/src/platform.ts
@@ -316,7 +316,7 @@ export class WebSocketTransport implements ConnectionTransport {
 
   onmessage?: (message: string) => void;
   onclose?: () => void;
-  private _connect: Promise<void>;
+  private _connect: Promise<{success: boolean, message?: string}>;
 
   constructor(url: string) {
     this._ws = (isNode ? new NodeWebSocket(url, [], {
@@ -324,8 +324,8 @@ export class WebSocketTransport implements ConnectionTransport {
       maxPayload: 256 * 1024 * 1024, // 256Mb
     }) : new WebSocket(url)) as WebSocket;
     this._connect = new Promise((fulfill, reject) => {
-      this._ws.addEventListener('open', () => fulfill());
-      this._ws.addEventListener('error', event => reject(new Error('WebSocket error: ' + (event as ErrorEvent).message)));
+      this._ws.addEventListener('open', () => fulfill({success: true}));
+      this._ws.addEventListener('error', event => fulfill({success: false, message: (event as ErrorEvent).message}));
     });
     // The 'ws' module in node sometimes sends us multiple messages in a single task.
     // In Web, all IO callbacks (e.g. WebSocket callbacks)
@@ -348,8 +348,15 @@ export class WebSocketTransport implements ConnectionTransport {
     this._ws.addEventListener('error', () => {});
   }
 
+  async _ensureConnected() {
+    const {success, message} = await this._connect;
+    if (success)
+      return;
+    throw new Error('WebSocket error: ' + message);
+  }
+
   async send(message: string) {
-    await this._connect;
+    await this._ensureConnected();
     this._ws.send(message);
   }