[SR-Users] What could cause an intermittent fault (28) with http_query()?

Hi All I seem to be experiencing an intermittent fault with the utils http_query() method. We are implementing a routing and white list component that is accessed via a REST api, however i have observed several occasions where this is logged: Jan 30 16:04:17 vs-kam-prod02 /usr/local/sbin/kamailio[13184]: ERROR: utils [functions.c:149]: http_query(): failed to perform curl (28) The indicated error number (28) seems to suggest a timeout is occurring with curl, however examining a capture of network traffic when this happens shows that a http request is not sent from the server to the destination at all, usually attempting a second call results in everything working correctly. As stated its intermittent in its nature and so I cannot reliably trigger this issue, other than through sheer repetition, so any ideas as to what could be causing this issue would be gratefully received,