Why does ChatGPT show 'Access Denied' even with a proxy?

OpenAI uses advanced IP reputation databases. If your proxy server's IP is shared by too many users or flagged as a data center IP, access will be blocked. Using a 'Residential' or 'Clean' node usually solves this.

Can Clash fix the 'Unable to load conversation' error in Claude?

Yes. This is often caused by fragmented routing where the main site is proxied but the websocket or API subdomains are not. Using a proper Clash rule provider ensures all Anthropic domains are routed through the same node.

Fix ChatGPT and Claude Access Denied: Clash Proxy Rules Guide 2026

The AI Access Challenge in 2026

In 2026, Large Language Models (LLMs) like ChatGPT (OpenAI) and Claude (Anthropic) have become essential productivity tools. However, as these platforms scale, they have implemented increasingly aggressive security measures to prevent botting, scraping, and access from unauthorized regions. For many users, even those using a VPN or proxy, the dreaded "Access Denied" or "Sorry, you have been blocked" message has become a frequent frustration.

The problem usually isn't that your proxy isn't working; it's that the quality of the proxy node or the precision of your routing rules is insufficient. Modern AI platforms don't just check if you are in a supported country; they analyze your IP reputation, check for "leaky" DNS queries, and monitor for inconsistent routing across subdomains. This is where Clash, with its powerful Mihomo core and rule-based routing, provides a superior solution compared to traditional "one-click" VPNs.

This guide will walk you through the technical reasons behind these blocks and provide a step-by-step configuration strategy to ensure reliable access to ChatGPT and Claude using Clash clients like Clash Verge Rev, FlClash, or Clash Meta.

Key Insight: AI blocks are rarely about the "location" and almost always about the "IP Reputation" and "DNS Integrity."

Why ChatGPT and Claude Block You

To fix the problem, we must first understand the detection mechanisms used by OpenAI and Anthropic. In 2026, they primarily use three layers of defense:

1. IP Reputation and Data Center Checks

Most cheap proxy nodes use IP addresses from major data centers (AWS, Google Cloud, DigitalOcean). AI platforms subscribe to databases (like IP2Location or MaxMind) that flag these IPs. If an IP is identified as a "Data Center," it is much more likely to be blocked or challenged with infinite CAPTCHAs. Residential IPs (ISP-assigned) are the gold standard for access.

2. DNS Leaks and Geo-Inconsistency

If your browser requests chatgpt.com through a US proxy, but your DNS query for that domain is resolved by your local ISP's DNS server in a restricted country, the AI platform can detect this mismatch. This is a "DNS Leak." Claude is particularly sensitive to this and will often show a "not available in your region" error even if the page loads.

3. Fragmented Routing

ChatGPT and Claude rely on dozens of subdomains and third-party services (CDN, authentication, telemetry). If your Clash rules only proxy the main domain but let the authentication service go "DIRECT," the login will fail. You need a comprehensive Rule Provider list that covers every associated domain.

Step 1: Selecting the Right Proxy Nodes

Not all Clash nodes are created equal. For AI access, your node selection strategy should prioritize quality over raw speed.

Avoid "Public" or "Free" Nodes: These are blacklisted almost instantly.
Prefer Residential (ISP) Nodes: Many high-end Clash providers now offer "Residential" or "Premium" lines. These use IPs that look like real home internet connections.
Stable US/UK/Singapore Nodes: While many regions are supported, US and UK nodes generally receive the most stable access and latest features.
Check for UDP Support: Some AI features (like voice mode) work better when the node supports UDP relay.

In your Clash client (e.g., Clash Verge Rev), create a specific Proxy Group just for AI. This allows you to switch nodes for ChatGPT without affecting your overall browsing.

Step 2: Configuring Clash Rule Providers

Manual rules like DOMAIN-SUFFIX,openai.com,Proxy are no longer enough. You should use Rule Providers, which are remotely maintained lists of all domains associated with a service.

Recommended Rule Sets for 2026

Add these to your config.yaml or your GUI's rule configuration:

rule-providers:
  openai:
    type: http
    behavior: domain
    url: "https://raw.githubusercontent.com/blackmatrix7/ios_rule_script/master/rule/Clash/OpenAI/OpenAI.yaml"
    path: ./ruleset/openai.yaml
    interval: 86400

  claude:
    type: http
    behavior: domain
    url: "https://raw.githubusercontent.com/blackmatrix7/ios_rule_script/master/rule/Clash/Claude/Claude.yaml"
    path: ./ruleset/claude.yaml
    interval: 86400

rules:
  - RULE-SET,openai,AI-Proxy
  - RULE-SET,claude,AI-Proxy
  - GEOIP,CN,DIRECT
  - MATCH,Others

By using these rule sets, you ensure that subdomains like auth0.openai.com, cdn.oaistatic.com, and anthropic.com all route through your selected AI-Proxy group.

Step 3: Enabling Clash TUN Mode

System Proxy mode (HTTP proxy) is often ignored by background processes and certain browser components. To ensure 100% of the traffic—including DNS—is captured by Clash, you must enable TUN Mode.

Grant Admin Privileges: On Windows or macOS, Clash needs permission to create a virtual network adapter. Ensure you run the app as Administrator.
Toggle TUN Mode: In your client settings, find the "TUN Mode" switch and turn it on.
Verify the Adapter: Check your system network settings. You should see a new adapter (often named "clash" or "wintun").

TUN mode prevents DNS leaks by hijacking all port 53 traffic. When combined with fake-ip mode, it ensures that your browser never even knows the real IP of the AI server until the connection is safely tunneled.

Step 4: Fixing DNS Leaks with Fake-IP

Even with a proxy, your browser might try to resolve the IP address using your system's default DNS. If that DNS is local, the AI platform can see the query. In your Clash dns settings, use the following configuration:

dns:
  enable: true
  enhanced-mode: fake-ip
  fake-ip-range: 198.18.0.1/16
  default-nameserver:
    - 119.29.29.29
    - 1.1.1.1
  nameserver:
    - https://doh.pub/dns-query
    - https://dns.cloudflare.com/dns-query

Fake-IP works by giving the browser a "fake" internal IP immediately, while Clash handles the real resolution secretly through the proxy tunnel. This is the most effective way to bypass geo-blocks in 2026.

Common Errors and Troubleshooting

Error 1020: Access Denied

This is a Cloudflare-level block. It means your IP is on a blacklist. Fix: Switch to a different node immediately. Do not keep refreshing, as this will flag your account for suspicious activity.

Claude: "App is not available in your region"

This is usually a DNS leak or a browser cache issue. Fix: Enable TUN mode, clear your browser's cookies/cache for anthropic.com and claude.ai, or use an Incognito/Private window after starting Clash.

Infinite CAPTCHA Loops

This happens when your IP has a high "spam score." Fix: Disable any browser extensions that might be leaking your real location (like WebRTC leakers) and switch to a node with a lower user density.

Clash vs. Standard VPN for AI

Why do we recommend Clash over a standard commercial VPN for ChatGPT and Claude?

Feature	Standard VPN	Clash (Mihomo)
Routing Control	All or Nothing	Granular (AI via Proxy, local via Direct)
DNS Leak Protection	Basic	Advanced (Fake-IP / DNS Hijack)
IP Selection	Randomized	User-defined (Pick specific clean nodes)
Rule Maintenance	None	Automatic via Rule Providers

For a professional workflow, you cannot afford to have your entire internet speed throttled by a VPN just to use ChatGPT. Clash allows you to maintain high speeds for local tasks while keeping your AI tools behind a secure, clean proxy tunnel.

Advanced Tip: Blocking WebRTC Leaks

Even with Clash and TUN mode, some browsers (especially Chrome) can leak your real local IP through a protocol called WebRTC, which is used for video calls. AI platforms can use this to see "behind" your proxy.

To prevent this, you should install a browser extension like "WebRTC Leak Prevent" or manually disable WebRTC in Firefox (via about:config). This adds an extra layer of invisibility to your setup, making your proxy connection indistinguishable from a native user in the target country.

Why Use Our Optimized Clash Clients?

Configuring raw YAML files can be daunting. The clients available on our download page—such as Clash Verge Rev and FlClash—come with built-in GUI options for TUN mode, DNS settings, and Rule Providers. Instead of manually editing text files, you can simply paste a subscription URL and toggle the "AI" group with a single click.

Standard VPN apps often fail to keep up with the rapid changes in AI platform blocking strategies. Because Clash is open-source and community-driven, rule sets are updated daily by thousands of users worldwide. When OpenAI adds a new domain for its search features, the community rule providers are updated within hours, ensuring you never lose access.

Download Clash free for every platform →