Cursor Not Working? Fix Sign-In, Chat, and Tab

If Cursor keeps looping through sign-in, or both chat and Tab stop responding, do not start with a reinstall. Open the Cursor status page first. Incidents can affect a single model, so read the model-specific notices rather than relying only on the overall status.

If no incident is active, quit Cursor completely, reopen it, and follow the section that matches the broken feature.

Sign-in finishes in the browser but not the app

Run Cursor Settings > Network > Run Diagnostics first. If your environment uses a VPN, proxy, or firewall, inspect the diagnostic result and its allowlist checks.

Cursor documents that a VPN can trigger a suspicious activity block. If you see that message, turn off the VPN, wait a few minutes, and try another sign-in provider such as Google or GitHub.

On a company or school network, confirm that the firewall allows *.cursor.sh, *.cursor-cdn.com, and *.cursorapi.com. Those are the domains listed in Cursor’s official troubleshooting guide.

Chat does not respond

Check the editor for a usage-limit notification. The Hobby plan includes limited Agent requests and Tab completions, but Cursor does not publish a fixed request count on its pricing page. Review your dashboard before changing plans. If you choose usage-based billing, set a monthly spending limit first and confirm the amount; otherwise move to a plan that fits your budget. When there is no limit warning, investigate the network or selected model first.

To see whether the failure affects only one model, switch the chat selector to another option such as Auto and send a short prompt.

Corporate security software and proxies can block the HTTP/2 connection used for streaming responses; Zscaler is a common example. Set Cursor Settings > Network > HTTP Compatibility Mode to HTTP/1.1, then restart Cursor. This is Cursor’s documented workaround.

Tab completions disappear

Open Cursor Settings > Tab and confirm that Tab is enabled. Then select the Tab status icon in the lower-right corner. Tab may be snoozed, disabled globally, or disabled only for a file type. If suggestions disappear only in Markdown or JSON files, check the per-language controls.

If another inline-completion extension such as GitHub Copilot is active, temporarily disable one of the two. Users report extension conflicts, although Cursor does not list this as an official fix.

When to check usage or reinstall

Plan inclusions and prices can change, so check Cursor’s current pricing and usage-limit pages instead of relying on an amount quoted here. In the dashboard, review remaining usage and any usage-based charges. Set a monthly spending limit before enabling usage-based billing.

For a blank window, first quit and reopen Cursor completely. If it remains blank, reinstall from the official download. Clear Editor History can remove cached state, but it may also remove local editor history; back up important work and use it only as a last resort.

If the problem remains, post in the official Cursor forum with your Cursor version, operating system, and whether you are on a corporate network or VPN. Those details help separate account, network, and application failures that otherwise look identical.