I'm using the Wp-QuickLaTeX plugin, but it cannot connect to QuickLaTeX server because my hoster (free.fr) has disabled any kinds of communication with external servers.
*** QuickLaTeX cannot compile formula: f(x) *** Error message: Cannot connect to QuickLaTeX server: Failed to connect to 220.127.116.11: Unknown error 101 Please make sure your server/PHP settings allow HTTP requests to external resources ("allow_url_fopen", etc.) These links might help in finding solution: http://wordpress.org/extend/plugins/core-control/ http://wordpress.org/support/topic/an-unexpected-http-error-occurred-during-the-api-request-on-wordpress-3?replies=37
So after having installed core-control, I've consulted the last link in error message for resolution to change hosting provider, but I didn't succeed in :(
This is the result when I test the external HTTP access :
cURL => "An Error has occured: Failed to connect to 18.104.22.168: Unknown error 101"
PHP Streams => "Whilst an error was not returned, The server returned an unexpected result: , HTTP result: 0"
PHP fsockopen() => "An Error has occured: 101: Network is unreachable"
http_request_timeout 5 5
http_request_redirection_count 5 5
http_request_version '1.0' '1.0'
http_headers_useragent 'WordPress/3.5.1; http://***.free.fr' 'WordPress/3.5.1; http://***.free.fr'
block_local_requests false false
use_fsockopen_transport true true
use_streams_transport true true
use_curl_transport true true
https_local_ssl_verify true true
https_ssl_verify true true