I have a 3cx version 188.8.131.52.3. I want to have my office 365 contacts in 3cx. I followed the guidelines in https://www.3cx.com/docs/how-to-create-impersonated-user/ after that i followed this link https://www.3cx.com/docs/manual/phonebook-directory/ Configuring the Exchange Connector (MS Exchange Sync) But the contacts wil not turn up in my 3cx. After i have dowloaded the 3cxSystemService.log i found the following error: 018/03/20 13:56:49.479|10658|0054|Excpt|Microsoft.Exchange.WebServices.Data.ServiceRequestException: The request failed. The remote server returned an error: (401) Unauthorized. ---> System.Net.WebException: The remote server returned an error: (401) Unauthorized. Can somebody tell me what the problem is ?