How to troubleshoot LDAP connection

I have just tried to add an LDAP directory on a friend’s computer in Thunderbird. It would not work. But I have the same directory on my computer and the settings are the same. What possible setting is there to check that may stop it working in one setup while it works fine in another with the same values in the properties?

Is Address book not accessible after upgrade to 78 any help?

Maybe this topic