With osTicket 1.9.3, PHP 5.3.24, IIS 7.5, on Windows 2008R2, screenshot details below, I am able to just fill in the Microsoft Active directory fields and users and staff are Authenticated.
With osTicket 1.12.2, php 7.0, IIS 8.5, on Windows server 2012 screenshot details below, I fill in the Microsoft Active directory fields and I get error messages in the Generic configuration for LDAP.
Why do the same settings not work in 1.12.2?
osticket 1.9.3 information 
osticket 1.12.2 information 
osticket 1.9.3 working ldap plugin 
osticket 1.12.2 not working ldap plugin 
Microsoft Active Directory Authentication plugin error
- Edited
Neither config appears to have a ldap server specified?
Does your ldap server allow anonymous bind?
The first screen shot shows Active Directory selected. The second does not.
We do not have control over our ldap servers so not sure what settings are set.
Why would not having the ldap server specified in 1.9 work but not in 1.12. According to the headers Generic config for LDAP is not necessary if Active Directory is configured above?
I have selected active directory but still no dice.
No idea.
Since the LDAP plugin was released I've been using it on multiple sites up to and including 1.12.2.
figured it out, if I put the l default domain in the ldap server box it works.
I guess this should be put in as a bug since the directions say you only have to put the domain in the default domain field.
5 days later
It generally depends on your configuration (and DNS) as to if it can auto discover the LDAP server.