How to Fix Claude Stuck on Checking Your Browser

Why Claude gets stuck on the browser verification screen

To protect its infrastructure from automated scraping bots, distributed denial-of-service (DDoS) attacks, and credential stuffing, Claude employs Cloudflare's security shields. When you visit the site, Cloudflare runs a silent JavaScript challenge to confirm your browser environment is genuine, your system clock is accurate, and your IP address is clean.

When Claude is experiencing a major outage or high-traffic event, Anthropic often raises their Cloudflare security level to "Under Attack" mode. This forces aggressive, frequent checks. If your browser fails to pass these background checks due to blocked cookies, outdated browser components, or bad network routing, you will get stuck in an infinite, non-responsive loading loop.

Steps to resolve the browser check loop

1. Perform a hard reload and clear site-specific cookies Corruption in your local session files can prevent the Cloudflare verification token from writing to your browser, trapping you in a loop. 1. Navigate to the Claude login page. 2. Click the **padlock icon** (or settings icon) directly to the left of the URL in your browser's address bar. 3. Click on **Site settings** or **Cookies and site data**. 4. Select **Clear data** or delete all cookies listed under `claude.ai`. 5. Press **Ctrl + F5** (Windows) or **Cmd + Shift + R** (macOS) to force a clean reload and try the challenge again.

2. Disable strict tracking shields and ad blockers Many advanced privacy tools, script blockers, and built-in browser shields block the specific Cloudflare scripts required to evaluate your browser's legitimacy. 1. If you are using **Brave**, click the orange lion shield icon in the address bar and turn off shields for `claude.ai`. 2. If you are using extensions like **uBlock Origin, Ghostery, or NoScript**, temporarily disable them or add `claude.ai` to your whitelist. 3. Reload the page and allow the browser verification box to spin uninterrupted.

3. Check and synchronize your system clock Cloudflare's security handshakes rely on cryptographic timestamps. If your operating system's system clock is off by even a single minute, the verification token will be flagged as expired or invalid. 1. **Windows**: Right-click the system clock in the taskbar, select **Adjust date and time**, and click **Sync now** under the "Synchronize your clock" setting. 2. **macOS**: Go to **System Settings > General > Date & Time**, toggle the "Set time and date automatically" option off and back on to force a sync. 3. Reload your browser and try logging in again.

4. Switch networks or disable VPN nodes If your current IP address belongs to a range frequently flagged for spam or malicious API scraping (a common issue with public VPNs or shared hosting networks), Cloudflare will repeatedly reject your browser signature. 1. Temporarily turn off any **VPN** or proxy services you are running. 2. If possible, disconnect from your local Wi-Fi and connect to your mobile phone's hotspot to get a fresh consumer IP address. 3. Attempt to complete the verification check on this new network.

5. Disable conflicting browser extensions Some extensions that modify your User-Agent header, block canvas fingerprinting, or manage automated processes can look identical to bot activity. 1. Open an **Incognito/Private window** where extensions are disabled by default. 2. If Claude loads successfully in Incognito, go back to your main window and temporarily disable extensions one-by-one to isolate the culprit (especially those related to privacy, dark mode, or developer tools).

When to escalate

If you have synchronized your system clock, cleared all cookies, disabled extensions, and still cannot get past the Cloudflare loop on any device, check if there is an active global outage.

Go to status.anthropic.com and look for incidents labeled "Degraded performance" or "Cloudflare DNS issues." If an outage is active, you must wait for Anthropic to lower their global security profile. If the status page is green, try accessing Claude via your smartphone's mobile browser on cellular data. If that works, the issue is isolated to your local ISP or router configuration, which may require resetting your home modem to obtain a clean IP address.