[SOLVED] Integrity Server authentication on WS2016 doesn't work anymore

Hi,

I'm facing a pretty annoying issue since few days and I can't figure out what's happening. We run a bunch of Integrity Server virtual machines for development purposes. Those servers authenticate users on our Windows Server 2016 AD, and it was working like a charm until some days.

Now, we can't authenticate on any of those VMs. I suspect this is because of some automatic update in WS2016, but it's pretty hard to diagnose. The Integrity Server log shows the following traces:

2018-05-14 14:39:22,970 INFO [STDOUT] Debug is true storeKey false useTicketCache false useKeyTab false doNotPrompt false ticketCache is null isInitiator true KeyTab is null refreshKrb5Config is true principal is null tryFirstPass is false useFirstPass is false storePass is false clearPass is false
2018-05-14 14:39:22,970 INFO [STDOUT] Refreshing Kerberos configuration
2018-05-14 14:39:22,970 INFO [STDOUT] 		[Krb5LoginModule] user entered username: <a login>
2018-05-14 14:40:13,908 WARN [mksis.IntegrityServer] * * * * WARNING * * * * (5): RMI Executor-thread-9: Connection terminated because it is no longer responding to messages
2018-05-14 14:40:52,986 INFO [STDOUT] 		[Krb5LoginModule] authentication failed 
Receive timed out

Because of the "timed out", one may say the VM doesn't communicate with the AD anymore but this is not true:

- we can ping the AD server

- by running ADExplorer, we can authenticate on the AD from any Integrity Server virtual machine

We also have a scan to mail machine which also authenticates users on the AD, and it works. Any idea of what could be wrong? Thanks.