Thanks for reporting this, and sorry for the instability here. I understand it can be frustrating.
From what you shared, this may be related to the local network path Cursor is using, such as VPN routing, proxy/firewall behavior, DNS, or TLS/HTTP inspection. That said, we still want to help narrow it down.
A few things worth trying:
Temporarily disable VPN, proxy, and then rerun the Network diagnostics.
Try a different network, such as a mobile hotspot, to see whether the HTTP/1.1 and Agent tests become stable.
Make sure Cursor is updated to the latest version.
If you are on a managed or corporate network, check whether Cursor traffic is being intercepted or rate-limited by firewall/proxy rules.
Restart Cursor after changing network settings, then rerun the diagnostics from Settings → Network.
If the issue keeps happening after those steps, please reach out to us with the diagnostics results and a recent request ID from a failed Agent request. That will let us check whether anything unusual is showing up on our side and help determine whether this is a Cursor service issue or something in the network path.