Hey, thanks for the report. This is a common issue we’ve recently seen with a few users. It’s usually caused by MCP server settings or third-party API key settings that interfere with connecting to Anthropic.
Since it only happens on this machine, it’s likely related to local Cursor config. Please try this:
- Cursor Settings > Tools & MCP: If you have any MCP servers connected (Perplexity, Figma, or custom), temporarily disable them all.
- Cursor Settings > Models: Make sure Override OpenAI Base URL is turned off. If you have any third-party API keys set (Anthropic or OpenAI), temporarily disable those too.
- Sign out and sign back in (Cursor Settings > Sign Out, then Sign In).
- Test in a new chat in a different project folder.
This helped several users with the exact same error:
- Trouble connecting to the model provider for all Anthropic and Open AI models: Trouble connecting to the model provider for all Anthropic and Open AI models
- Cursor completely unusable - “Provider Error” on all models: Cursor completely unusable - "Provider Error" on all models
If that doesn’t help, and since the issue is specific to this machine and only affects Anthropic models:
- Go to Cursor Settings > Network > Run Diagnostics and share the results.
- Try disabling HTTP/2: App Settings
Ctrl + ,search for HTTP/2, then enable Disable HTTP/2. - Check whether your firewall or antivirus on this PC is blocking any endpoints.
Let me know how it goes.