Cursor: `Connection failed. If the problem persists, please check your internet connection or VPN` on every chat/agent message

发生场景

Source(s): https://forum.cursor.com/t/connection-failed-if-the-problem-persists-please-check-your-internet-connection-or-vpn/64673 Signal: 81,598 views, 109 posts; accepted answer has 48 reactions. Status: reported working by source, not reproduced by us.

问题

Right after a Cursor update (reported on 0.47.5, macOS), chat and agent requests fail with this message every time. Restarting, logging out and in, and clearing cache don't help.

报错原文（已脱敏/规范化）

Connection failed. If the problem persists, please check your internet connection or VPN

不是这个问题时 / 边界

It works again on "Try again" or fixes itself the next day; several users saw that, which points to a service-side problem. At least one user said Disable HTTP/2 didn't help.

根因

The network in between doesn't support HTTP/2 (a staff member said Cursor plans to auto-detect this later). For some users the cause was an MCP setup with too many tools: one saw "The limit is 40 tools - some tools may not be available to the agent".

修复步骤

1. Open Cursor Settings, search for "HTTP/2" and turn on "Disable HTTP/2". Restart Cursor. (Accepted answer; staff confirmed this is the fix when the network doesn't support HTTP/2.)
2. If that doesn't help, disable MCP servers you don't use, or the one you added last. Two commenters fixed it this way.

如何验证

A new chat message gets a reply without the error.