Fix Claude Stuck on Sending Message Loading Spinner

Why Claude Gets Stuck Sending Messages

When you submit a prompt to Claude.ai and the send button turns into a spinning loading indicator indefinitely, the browser client has lost its connection to Anthropic's real-time message stream.

Unlike an explicit error page, the "stuck spinner" usually points to a breakdown in WebSocket communication, a corrupted local browser session, or an unhandled client-side JavaScript error. Below are the steps required to unblock the interface and restore message delivery.

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Step 1: Perform a Hard Refresh

A standard page reload often fails to clear stubborn memory leaks or stuck Service Workers in your browser. Perform a hard refresh to force the browser to redownload all Claude interface assets.

• Windows/Linux: Press Ctrl + F5 (or Ctrl + Shift + R).
• Mac (Chrome/Firefox): Press Cmd + Shift + R.
• Mac (Safari): Press Option + Cmd + E to empty the cache, then Cmd + R to reload.

Once the page reloads, sign back in if prompted and try submitting a simple one-word test message to verify if the connection is restored.

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Step 2: Check for Blocked WebSockets

Claude.ai relies on WebSockets (persistent, two-way communication channels) to stream responses back to your browser in real time. If WebSockets are blocked by your local environment, your messages will upload, but the interface will spin forever waiting for the stream to start.

1. Disable VPNs and Proxies: Some corporate VPNs, proxy servers, or custom DNS configurations intercept or drop WebSocket connections. Temporarily disconnect your VPN.
2. Check Your Ad-Blocker: Browser extensions like uBlock Origin, Privacy Badger, or built-in browser shields (like Brave Shields) can mistakenly block Claude's WebSocket endpoints. Add https://claude.ai to your extension's whitelist or temporarily turn off the adblocker to test.
3. Test on Mobile Data: Disconnect your computer from your current Wi-Fi network, connect to a mobile hotspot, and try sending a message. If this works, your local router or ISP firewall is blocking the stream.

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Step 3: Clear Claude's Site-Specific Data

Corrupted cookies or outdated local storage values can put the Claude interface into an unrecoverable state, preventing the UI from properly processing the API handshake.

For Google Chrome and Chromium-based browsers: 1. Open claude.ai in your browser. 2. Click the padlock or tune icon to the left of the URL in the address bar. 3. Select Site settings. 4. Click the Clear data button at the top of the settings page. 5. Go back to Claude.ai, refresh the page, sign back in, and test.

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Step 4: Split Large Prompts or Files

If the spinner only occurs when you paste massive amounts of text or upload multiple files, you may be hitting an undocumented payload size limit that the web interface is failing to handle gracefully.

1. Open a new chat session.
2. Copy a small fraction of your original prompt.
3. If the small prompt processes immediately, the issue is related to the size or format of your files.
4. Break your large documents into smaller text sections and feed them to Claude sequentially rather than all at once.

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Step 5: Check the Browser Console for Errors

If the steps above do not work, look at the browser's developer console to pinpoint the exact failure mechanism.

1. Right-click anywhere on the Claude web page and select Inspect.
2. Click on the Console tab.
3. Look for red error messages.
4. If you see errors like WebSocket connection to 'wss://...' failed, your network is actively blocking the streaming protocol.
5. If you see Uncaught TypeError or script loading failures, the issue is likely a bug in the current deployment of the web app or a conflict with an active browser extension.

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When to Escalate

If you have cleared your site data, confirmed WebSockets work on other platforms, disabled all extensions, and the spinner still hangs on multiple different browsers, the issue is likely a localized outage of Anthropic's frontend routing layers. Check their status page or the community forums to see if others are reporting the same issue, or submit a bug report via the "Help" button in the bottom-right corner of the Claude interface if you can access it.