Hi
check out
http://support.microsoft.com/kb/958804, that describes this same error (DsGetDcName returns error 1355). According to that doc, it implies some config issue with your domain.
We also added in 7.2.0 an override option to bypass this particular issue, with a registry setting, but it requires you to discover the GUID of the domain object for your domain.
The overrides are in (since you're on x64)
HKEY_LOCAL_MACHINE\Software\WOW6432Node\Qbik Software\WinGate\Users\ADProvider\Settings
ForceDomain (REG_DWORD): 1=use forced value of domain
DomainOverride (REG_SZ): overridden domain, e.g. qbik.local
ForceDomainGUID (REG_DWORD): 1=use forced value of domain GUID
DomainGUIDOverride (REG_SZ): GUID of your domain object (including curly braces).
I know 2 ways to obtain the GUID of your domain:
1. an LDAP browser (e.g. Softerra LDAP browser).
Connect to your AD server, and browse to the DC=[your domain name] object, and look for the ObjectGUID property
2. in the DNS MMC snapin on the domain controller under
Forward Lookup Zones\[your domain name]\_msdcs\domains - The sub-key name is the GUID (but without curly braces).
Adrien