Troubleshooting target server connectivity

At the Verification stage of the Target server connection wizard, the program checks if it can establish a connection to the target server. The program attempts to access the administrator's mailbox using EWS (Exchange Web Services) API. It then tries to enumerate the Inbox folders on a mailbox. During that process, you may receive the following errors: 

The request failed. The remote server returned an error: (401) Unauthorized.

This error indicates that:

  • the admin's password entered in the previous step is incorrect,
  • or the credentials belong to a non-administrative user,
  • multi-factor authentication (MFA) is enabled for the admin account (Office 365 only).

To fix the problem, be sure to:

  • enter credentials of a user with sufficient administrative rights,
  • enter the correct password,
  • use the app password instead of your regular Office 365 password if MFA is enabled for the admin account. Learn more.
  • disable MFA for the admin account (Office 365 only).
The request failed. Unable to connect to the remote server.

This error occurs when the domain name in the administrator's UPN is misspelled. Go to the previous step of the connection wizard and make sure to enter correct credentials.

In the case of on-premises Exchange connection, a similar message is also shown when the EWS URL is wrong. Go to the Target server step of the wizard and enter the correct EWS URL.

The Autodiscover service couldn't be located.

This error might indicate that:

  • the domain name in the admin's email address was misspelled. Go to the previous step of the wizard and make sure to enter the correct data;
  • the software version that you have does not support TLS 1.2 and is not able to connect to your Office 365. Learn more
The request failed. The underlying connection was closed: An unexpected error occurred on a receive.

The reason you experience this problem is that you might be using a software version that does not support TLS 1.2 and is therefore not able to connect to Office 365 services. Make sure you have the latest version of CodeTwo Out of Office Manager installed. Read more about problems related to old TLS protocols and how to troubleshoot them

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