One of our clients is having an issue where Laserfiche Forms reports this error in the Event Viewer:

4/15/2016 4:08:35 PM
Message: The server is not operational.

Stack trace:    at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
   at System.DirectoryServices.DirectoryEntry.Bind()
   at System.DirectoryServices.DirectoryEntry.get_AdsObject()
   at System.DirectoryServices.DirectorySearcher.FindAll(Boolean findMoreThanOne)
   at System.DirectoryServices.DirectorySearcher.FindOne()
   at Laserfiche.Forms.CommonUtils.FormsUserSyncer.LDAPHelper.DirectoryEntrySearch(String filter, String[] propertiesToLoad)
   at Laserfiche.Forms.CommonUtils.FormsUserSyncer.LDAPHelper.GetGroupBySIDAndName(SecurityIdentifier sid, String name)
   at Laserfiche.Forms.CommonUtils.FormsUserSyncer.RetrieveWinGroupsFromRepository(cf_tenants defaultTenant, cf_roles basicRole)

The error is reported twice per day, with 1 second or less in between. It is reported at the same time every day. It is also only reported on the Forms Server on the DMZ.

Based on this information, and the stack trace, my guess is that the DMZ Forms Server is trying to contact the domain controller inside the network when it tries to synchronize users (a few of them are Windows users), but fails. But I wanted to run it by Laserfiche first before I start fiddling with firewall settings.