Why AI tools fail on work networks

If an AI tool works at home but fails at the office, the provider is probably fine. Company networks add proxies, firewalls and certificate checks, and these can interfere with tools that stream responses.

Proxies and HTTP/2

Cursor streams responses over HTTP/2, and its documentation says some corporate proxies, such as Zscaler, block it. The suggested fix is to switch Cursor’s HTTP compatibility mode to HTTP/1.1 in its network settings and restart. Cursor also has built-in network diagnostics in its settings that check its connection to its servers.

Proxy settings and certificates

GitHub’s documentation on Copilot network errors describes timeouts and connection resets that come from a proxy blocking the connection, and certificate errors such as “unable to verify the first certificate”. These appear when a proxy inspects encrypted traffic with a certificate your machine does not recognise. GitHub says Copilot does not support proxy addresses that begin with https://, and needs basic or Kerberos authentication where one is required. It suggests testing your connection with curl and asking your IT team to configure the proxy or install the certificate properly.

Firewalls and allowlists

Where a firewall blocks outbound traffic, the tool’s domains need to be allowed. Cursor lists cursor.sh, cursor-cdn.com, cursorapi.com and cursorvm.com, including subdomains. GitHub’s documentation has a separate page on firewall settings for Copilot.

VPNs

Cursor says a VPN can trigger a “suspicious activity” block. Turning the VPN off, starting a fresh chat or signing in another way can help.
After you disconnect from a VPN, Cursor suggests fully restarting it, not just reloading the window, so old DNS settings are cleared.
GitHub lists VPNs and firewalls among the things that can stop Copilot reaching its servers.

Remote and SSH sessions

Cursor’s documentation notes that AI requests go from your own machine to Cursor, not from the remote host. When working over SSH, your local internet connection is what matters.

Copilot at work is a different product

Microsoft’s troubleshooting article for Copilot in Microsoft 365 apps lists causes unrelated to outages: a newly assigned licence that has not taken effect, being signed in with both a personal and a work account, device-based licensing, the wrong update channel, and privacy settings that block connected experiences. Our Microsoft Copilot page covers the consumer app, not this one.

How to tell it is your network

If our page and the provider’s status page both look healthy, try the same tool on mobile data or a home connection. If it works there, take the details above to your IT team. If it fails everywhere, read what to do when an AI chatbot stops working.

Sources

Read on 8 October 2026. Providers change their documentation, so check it for anything important.