- On iOS/MacOS devices it is not possible to load website in any browser with an error like below:
CONFIG_TEXT: The operation couldn’t be completed. Protocol error
Blank page may also be shown
- Accessing website from Debian/Ubuntu command line returns an error similar to below one:
# curl -vvv -k -L -I example.com
* http2 error: Invalid HTTP header field was received: frame type: 1, stream: 1, name: [upgrade], value: [h2,h2c]
* HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)
* stopped the pause stream!
* Connection #1 to host example.com left intact
curl: (92) HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)
- nginx set up as proxy server in Domains > example.com > Apache & nginx settings > Proxy Mode;
Issue is caused by Apache bug 59311: when
http2 module is enabled both for Apache and nginx, Apache sends incorrect header to nginx. When nginx used as proxy, it passes this invalid header further to browsers causing them refuse to connect.
http2is enabled both for Apache and nginx is not supported: when nginx acts as a proxy, only it interacts with the browsers. However, in order to track impact of this behavior internal request with ID PPPM-12381 has been created.
To fix the issue:
- Login into Plesk;
http2for Apache in Tools & Settings > Apache Web Server.