LDAPS - working but throws errors

Hi everyone,

i implemented LDAPS for Sophos UTM some time ago and everything is working fine i thought.

But due to the Microsoft LDAP Signing Requirements i had a deeper look into logging LDAP.

I get this error all the time:
Internal event: An LDAP client connection was closed because of an error.

Client IP:
FW IP Adress:41660

Additional Data
Error value:
3 The system cannot find the path specified.
Internal ID:
c0605e5

And the login try is counted 2 times!

Anyone else experiencing this?

I have set the logging here: 

From <https://support.microsoft.com/en-us/help/314980/how-to-configure-active-directory-and-lds-diagnostic-event-logging> 

Best regards

Stephan