Issue ADSYNc Active Directory sinchronization failed

HI team

How are you? I need your help me, about I have a problem with a Active Directory Sinchronization, because at this moment I oppressed the key "Preview and Sync". It shows on the application "sync finished with errors" and the next logs :

10:31:30.249 a.m. Error [Th 12] Active Directory synchronization failed. Reason: SophosCloudADSyncLib.DisplayableException: Error making a request over LDAP. Please review the connection settings you specified. The LDAP server returned the following error: 0000208D: NameErr: DSID-03100241, problem 2001 (NO_OBJECT), data 0, best match of:
'OU=CSF,DC=csf,DC=local'
---> System.DirectoryServices.Protocols.DirectoryOperationException: The object does not exist.
at System.DirectoryServices.Protocols.LdapConnection.ConstructResponse(Int32 messageId, LdapOperation operation, ResultAll resultType, TimeSpan requestTimeOut, Boolean exceptionOnTimeOut)
at System.DirectoryServices.Protocols.LdapConnection.SendRequest(DirectoryRequest request, TimeSpan requestTimeout)
at SophosCloudADSyncLib.LdapRequestCommand.SyncExeImpl(Object runtimeArg)
--- End of inner exception stack trace ---
at SophosCloudADSyncLib.LdapRequestCommand.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosCloudADSyncLib.LdapSearchCommand.searchLdap(SearchParams searchParams)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosADSync.GetAllADEntriesCommand.GetEntries(String defaultFilter, String additionalFilter, String searchItemName, SearchBase searchBase, String[] searches, HashSet`1 mailboxes)
at SophosADSync.GetAllADEntriesCommand.GetMailboxes(SearchBase searchBase, HashSet`1 mailboxes)
at SophosADSync.GetAllADEntriesCommand.GetObjectsInTree[T](LDAPFilters ldapFilter, SearchBase searchBase, HashSet`1 objects, GetObjects`1 getObjectsDelegate)
at SophosADSync.GetAllADEntriesCommand.GetObjectsInForest[T](LDAPFilters ldapFilter, HashSet`1 objects, GetObjects`1 getObjectsDelegate)
at SophosADSync.GetAllADEntriesCommand.GetObjectsInForest[T](LDAPFilters ldapFilter, GetObjects`1 getObjectsDelegate)
at SophosADSync.GetAllADEntriesCommand.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosADSync.GetChangesCmd.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosADSync.ADSyncCommand.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosADSync.ChangeStateAndADSyncCommand.SyncExeImpl(Object runtimeArg)
10:31:30.249 a.m. Error [Th 12] Context for failure: RecurringCommand=>ScheduledCommand=>ChangeStateAndADSyncCommand=>ADSyncCommand=>GetChangesCmd=>GetAllADEntriesCommand=>LdapSearchCommand=>LdapRequestCommand(707)

10:32:33.359 a.m. Error [Th 12] Active Directory synchronization failed. Reason: System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. ---> System.Security.Authentication.AuthenticationException: The remote certificate is invalid according to the validation procedure.
at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
--- End of inner exception stack trace ---
at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)
--- End of inner exception stack trace ---
at CommandLib.HttpRequestCommand.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at CommandLib.RetryableCommand.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosADSync.SophosCloudWebClient.MakeRequest(String address, HttpMethod method, Byte[] data, Dictionary`2 headers, Int32 maxRetries)
at SophosADSync.SophosCloudWebClient.MakeRequest[T](String address, HttpMethod method, Byte[] data, Dictionary`2 headers, Int32 maxRetries)
at SophosADSync.SophosCloudWebClient.SubmitPreviewSyncData(LDAPData ldapData, Boolean writeToDisk)
at SophosADSync.ADSyncCommand.PreviewSync(LDAPData ldapData, Boolean isManualSync)
at SophosADSync.ADSyncCommand.SyncExeImpl(Object runtimeArg)
at CommandLib.Command.BaseSyncExecute(Object runtimeArg, Command owner)
at SophosADSync.ChangeStateAndADSyncCommand.SyncExeImpl(Object runtimeArg)
10:32:33.359 a.m. Error [Th 12] Context for failure: RecurringCommand=>ScheduledCommand=>ChangeStateAndADSyncCommand=>ADSyncCommand=>RetryableCommand=>HttpRequestCommand(814)