JavaScript file loading error: net::ERR_HTTP2_PROTOCOL_ERROR

Chrome console shows net::ERR_HTTP2_PROTOCOL_ERROR for JS or CSS files, even though the files exist and return HTTP 200 OK. Why does this happen and how can I fix it?

This error isn’t about missing files—it signals a low-level HTTP/2 protocol failure, often due to mismatched content length, abrupt stream resets, or partial responses ([turn0search0](Stack Overflow+15Stack Overflow+15bytezonex.com+15), turn0search5. Typical causes: • The server runs out of disk space, so it can’t deliver the complete payload, leading to truncated data vs. content-length mismatch ([turn0search0](Stack Overflow). • HTTP/2 misconfiguration in reverse proxy or load balancer (e.g. idle timeouts, header size/errors, chunking-related issues) ([turn0search5](Stack Overflow+2CSDN Blog+2Jianshu+2). • Double gzip compression when both Node.js and NGINX/Brotli or pagespeed modules compress assets ([turn0search2](Managed WordPress Hosting+6Server Fault+6ItsMyCode+6). • Client-side interference: stale browser cache, problematic Chrome extensions, or QUIC protocol conflict (turn0search12. Intermittent symptoms: • Works on mobile devices or other browsers but fails in Chrome. • Right-click–opening the same URL may succeed while embedded loading fails ([turn0search8](CSDN Blog+15WordPress Development Stack Exchange+15Managed WordPress Hosting+15).

🨹 How to Fix It Layer Suggested Fix Server Check disk space and logs—free up storage and ensure HTTP/2 headers match real payload lengths ([turn0search0](UMA Technology+2ItsMyCode+2Jianshu+2).

Proxy / Load Balancer Tune HTTP/2 settings (e.g. proxy_max_temp_file_size 0, http2_max_header_size, http2_max_field_size, disable double compression) (turn0search5. Browser Clear cache and cookies, try incognito mode, disable QUIC in chrome://flags, disable suspicious extensions, or update Chrome to latest version (turn0search12. CDN / Deployment Bypass CDN or staging environment to isolate whether the proxy layer is triggering the error (turn0search5.

🧪 Example Scenario An Azure Front Door setup proxies JS/CSS files from a Node backend. When accessing via AFD, Chrome reports ERR_HTTP2_PROTOCOL_ERROR, but direct backend access works fine—indicating an issue at the edge proxy or SSL/HTTP/2 translation layer ([turn0search4](SSLInsights+8Microsoft Learn+8Stack Overflow+8).

🧷 Tags javascript, nodejs, http2, net::ERR_HTTP2_PROTOCOL_ERROR, static-files, nginx, azure, cdn, gzip, http2-config