Warning: fsockopen(): php_network_getaddresses: getaddrinfo failed: Name or service not known

Never seen such a situation !

Do you have once faced this problem ?

We use a fsockopen to retrieve a content from a URL [fsockopen ($url,
80, $errno, $errstr, 5);]. The content is dispalid corretly on a page
on one of our servers.
But on an other server (more-or-less same config.) the content is not
displaid !! with the error message ::

Warning: fsockopen(): php_network_getaddresses: getaddrinfo failed:
Name or service not known in /home/virtual/site1/fst/var/www/html/..php
on line 46

A config. probem of PHP or Linux server ? Never seen that in the past !

Many thanks for any comment or operating solutions.

Henry.