Les deux serveurs ne communiquent pas ensemble vérifier vos firewalls et votre configuration LDAP.
Si le problème persiste envoyé un impression écran de votre page système.
[Thu Jul 25 14:12:42.911161 2019] [:error] [pid 21232] [client 10.10.31.50:52182] PHP Warning: ldap_bind(): Unable to bind to server: Can't contact LDAP server in /var/www/gestsup/core/ldap.php on line 117, referer: http://gestsup.opacoise.fr/index.php?page=admin&subpage=parameters&tab=connector&ldaptest=1
[Thu Jul 25 14:31:57.076560 2019] [autoindex:error] [pid 26025] [client 10.10.31.54:59864] AH01276: Cannot serve directory /var/www/gestsup/upload/: No matching DirectoryIndex (index.html,index.cgi,index.pl,index.php,index.xhtml,index.htm) found, and server-generated directory index forbidden by Options directive
[Thu Jul 25 14:33:40.319542 2019] [:error] [pid 27890] [client 127.0.0.1:39236] script '/var/www/html/admin/api.php' not found or unable to stat
[Thu Jul 25 14:33:40.390935 2019] [:error] [pid 4732] [client ::1:55496] script '/var/www/html/admin/api.php' not found or unable to stat
OS : Linux gestsup 4.15.0-158-generic #166-Ubuntu SMP Fri Sep 17 19:37:52 UTC 2021 x86_64
MariaDB : 10.4.21-MariaDB-1:10.4.21+maria~bionic (base : bsup 183.8MB)
PHP : 7.3.30-1+ubuntu18.04.1+deb.sury.org+1
GestSup : 3.2.15 (8871 Tickets)