contacts not there with Exchange account


At work I’d like to implement EM client 6.0.2311.0 rather than Outlook as it enables me to synchronize my calendars with my NAS at home… And I like Em Client !
I could create an Exchange account and get my work emails and calendar synchronized in EM Client, but the contact list is empty and I get an error message regarding OAB.

In my account settings, within the “Mail, Calendar, Contact” sheet : Server : https://XXXXXXX/EWS/Exchange.asmx  with my correct credentials.

In “Offline Address Book” sheet : Server : https://XXX/OAB/571cd4d7-0c7a-4736-b634-23ae40623556/ with my credentials as well.

My compagny IT told me the server adress for OAB is  https://XXX/OAB/

Below is a copy of the log regarding the OAB problem;

Any clue ?
Many thanks

11:29:35 [email protected] [Offline Address Book]  Synchronizing folder list
11:29:35 [email protected] [Offline Address Book]  Synchronizing folder list
11:29:36 [email protected] [Offline Address Book]  Synchronizing folder ‘[email protected]/Global Address List/’
11:29:36 [email protected] [Exchange Web Services]  Synchronizing folder list
11:29:36 [email protected] [Offline Address Book]  MailExceptions.ConnectionException: Unable to read beyond the end of the stream. —> System.IO.EndOfStreamException: Unable to read beyond the end of the stream.
11:29:36    at System.IO.BinaryReader.FillBuffer(Int32 numBytes)
11:29:36    at System.IO.BinaryReader.ReadUInt32()
11:29:36    at MailClient.Protocols.OfflineAddressBook.OabReader.d__0.MoveNext()
11:29:36 at System.Collections.Generic.List1..ctor(IEnumerable1 collection)
11:29:36 at MailClient.Importers.Mapi.MapiContactConvert.ToContact(IEnumerable1 record)<br>11:29:36 at MailClient.Protocols.OfflineAddressBook.OabContactSynchronizer.RecordToContact(IEnumerable1 record)
11:29:36 at System.Linq.Enumerable.<>c__DisplayClass212.<select>b__20(TSource item, Int32 i)<br>11:29:36 at System.Linq.Enumerable.<selectyield>d__232.MoveNext()
11:29:36 at System.Linq.Enumerable.d__191.MoveNext()<br>11:29:36 at MailClient.Protocols.Common.ItemSynchronizeContext2.Synchronize[T](SynchronizationType synchronizationType, IEnumerable1 items, Func2 getUniqueId, Func3 hasChanged, Func2 isDeleted, Func2 convertItems, Action2 updateItem)
11:29:36 at MailClient.Protocols.OfflineAddressBook.OabContactSynchronizer.Synchronize(IItemSynchronizeContext1 synchronizeContext, Folder folder, CancellationToken cancellationToken)<br>11:29:36 at MailClient.Protocols.Common.ItemSynchronizer2.<>c__DisplayClass2e.<>c DisplayClass33.b 2a(WorkerStatus status, CancellationToken cancellationToken)
11:29:36 at MailClient.Protocols.OfflineAddressBook.OabGenericCommand.Execute(WorkerStatus status)