If you register an issue with login to IceWarp services using AD/LDAP connection, you probably have misconfiguration on the domain - Directory Service tab. In Deep Castle Gen 2 Update 1 is fixed regarding the parsing of the "Domain" option, which can cause unsuccessful login attempts to IceWarp services. The earlier version of IW parsed the string for the last ".", now IceWarp takes the whole string for parsing.
To check if the following article is your issue, setup the AD Sync log to "extended" (System - Logging - Debug - AD sync logs), perform a login, and check how IW is trying to log in (see log below).
AD Sync log:
SYSTEM [00007FF955FF6700] 14:16:17 AD auth on remote server performed (user=ex13.com\jakub.noga, pass=74e44e8aa0b75875a45bddeb733bdb59 server=adsrv.icewarp.com) result=0[49, (49) Invalid credentials]
Login in the provided log shows Invalid Credentials error because IW is trying to perform login with a different domain name than exist in the IW but in the wrong format. In this testing scenario should be domain written as "ex13", not "ex13.com".
To change this option, navigate to remote console - Domains & Accounts - <YourDomain> - Directory Service and change the option "Domain" to entry which you are normally using for login to AD (domain name). In this scenario was changed Domain tab from "ex13.com" to"ex13".
AD Sync log after the change:
SYSTEM [00007F2F85717700] 14:20:10 AD auth on remote server performed (user=ex13\jakub.noga, pass=74e44e8aa0b75875a45bddeb733bdb59 server=adsrv.icewarp.com) result=1