If the AI completion, chat, index, and agent in Cursor all fail, don't rush to reinstall it. According to the order of troubleshooting in the official documentation, the first step should be to run Network Diagnostics, because this kind of "the entire set of AI functions suddenly not working" is often caused by the network layer, especially HTTP/2, corporate proxies, VPNs, or firewalls.
Cursor relies on HTTP/2 to handle a lot of AI streaming responses. If your network environment does not support HTTP/2 well, or is interfered with by intermediaries such as enterprise proxies, VPNs, and Zscaler, it is easy to encounter problems that look like product pumping.
The correct order of troubleshooting is usually:
1. Open Cursor Settings > Network and run Network Diagnostics first.
2. See if the diagnosis has indicated an abnormal connection or handshake problem.
3. If you are under a corporate network, campus network, proxy link, or VPN, prioritize suspicion of the network environment rather than Cursor itself.
4. Search for HTTP/2 in the application settings, try to enable Disable HTTP/2, and let it fall back to HTTP/1.1.
Many people overlook step 4 because it's not in Cursor's own business settings, but in the application layer settings. The result is that the problem is obviously like "the model is blown up", but the current network environment is not suitable for HTTP/2 streaming links.
If HTTP/2 is closed and then restored immediately, it is basically a link compatibility problem. This is common in enterprise networks and does not mean that Cursor is broken. On the contrary, if Diagnostics is also normal and closing HTTP/2 does not improve, then look at the local resource usage, permissions, and index configuration, and the order is correct.
There is also a practical judgment: try changing hotspots or home networks. If your home network is normal and your company network is not normal, you should focus on proxies, certificates, VPNs, and gateways, rather than deleting profiles.
So if Cursor AI's functions suddenly fail, don't use the heaviest techniques first. Run Diagnostics first to see if HTTP/2 is stuck in the network environment. Many times, the real solution is not to reinstall the software, but to replace it with a cleaner network link.
