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ERR_HTTP2_PROTOCOL_ERROR: How to Fix It

The HTTP/2 connection between Chrome and the server was broken by an invalid response or a stream reset, usually by the server or something in between.

ERR_HTTP2_PROTOCOL_ERROR

Chrome and the server were talking HTTP/2, and something sent data that broke the protocol's rules or abruptly reset the request.

Quick checks

  • Reload once, then try a private window.
  • Try another browser and another network.
  • Pause antivirus web protection and VPNs.

Fixes on Mac

  1. Clear cache and disable extensions

    1. Delete cached images and files in Chrome's privacy settings.
    2. Test in a private window; if it works, disable extensions at chrome://extensions.

  2. Update Chrome

    1. Chrome › About Google Chrome installs updates; relaunch.

  3. Remove proxies and inspection tools

    1. Turn off proxies in System Settings › Network › Wi-Fi › Details › Proxies, and quit debugging proxies.

Fixes on Windows

  1. Check antivirus and reset network

    1. Disable HTTPS scanning in your antivirus to test.
    2. Run netsh winsock reset and restart.

Other devices

  1. Other devices

    1. Update the browser and try mobile data.

Still not working?

Site owners: this is usually server-side. Common causes:

  • Invalid response headers: connection-specific headers like Connection or Transfer-Encoding, or characters HTTP/2 forbids.
  • Response bodies cut off by a crashing backend or a timeout.
  • Proxies or CDNs with buffer limits too small for large headers or cookies.

Check the server's error log and reproduce with curl --http2 -v https://example.com/.

See what’s happening

LightAtom's connections view shows whether your browser connects to a proxy address instead of the site's servers, and which process runs that proxy.

Frequently asked questions

What causes ERR_HTTP2_PROTOCOL_ERROR?

An HTTP/2 stream reset or invalid frame: usually a server or proxy sending headers HTTP/2 doesn't allow, a backend that crashes mid-response, or security software interfering.

Is ERR_HTTP2_PROTOCOL_ERROR my fault?

Usually not, if it happens on one site in every browser and network. If it happens on many sites only on your Mac, look at extensions, antivirus and proxies.

Can I turn off HTTP/2 in Chrome?

Not with a normal setting. The fix belongs on the server or in the software interfering with the connection.

Related errors and tools

Related

LightAtom team

The people who build LightAtom, a network monitor for macOS.