Chrome network error · -337 · HTTP

ERR_HTTP2_PROTOCOL_ERROR

The server, or a proxy in front of it, broke the rules of HTTP/2 while sending the page, for example by sending an invalid header or resetting the stream.

Chromium's description

There is an HTTP/2 protocol error.

Chrome shows it as net::ERR_HTTP2_PROTOCOL_ERROR, error -337. puppeteer and Playwright report the same name when a page fails to load in Chromium.

Common causes

A response header that HTTP/2 forbids (such as Connection or Transfer-Encoding) or with an invalid value.
A backend that crashes or times out halfway through the response.
A proxy, CDN or load balancer that mishandles HTTP/2.
An antivirus or extension that modifies the traffic.

How to fix ERR_HTTP2_PROTOCOL_ERROR

Reload, try an incognito window and disable extensions.
Turn off HTTPS scanning of the antivirus.
Site owners: check server and proxy error logs, remove hop-by-hop headers, and look at response size and timeout limits.
Try the URL with curl --http2 -v to see where the stream is reset.

ERR_HTTP2_PROTOCOL_ERROR in the screenshot API

When the page itself fails to load with ERR_HTTP2_PROTOCOL_ERROR, the API answers 502 with the message The target website could not be loaded (ERR_HTTP2_PROTOCOL_ERROR). (target_unreachable). Not billed.

Only the page's own load can fail a render. An image, script or frame of the page that fails with a network error does not: the page is captured as the browser shows it without that resource.

Check whether a website loads

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Format

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Frequently asked questions

What does ERR_HTTP2_PROTOCOL_ERROR mean?

The server, or a proxy in front of it, broke the rules of HTTP/2 while sending the page, for example by sending an invalid header or resetting the stream.

How do I fix ERR_HTTP2_PROTOCOL_ERROR?

Reload, try an incognito window and disable extensions.

Is a screenshot that fails with ERR_HTTP2_PROTOCOL_ERROR billed?

No. Requests the screenshot API answers with an error are not billed.

Other common errors

ERR_CONNECTION_RESET ERR_CONNECTION_REFUSED ERR_CONNECTION_TIMED_OUT ERR_CACHE_MISS ERR_ADDRESS_UNREACHABLE ERR_TIMED_OUT ERR_SSL_PROTOCOL_ERROR ERR_CONNECTION_CLOSED ERR_QUIC_PROTOCOL_ERROR ERR_NAME_NOT_RESOLVED ERR_TOO_MANY_REDIRECTS ERR_NETWORK_CHANGED

All 249 Chrome network errors · Screenshot API errors

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