Troubleshooting server connection

If you configure the EWS connection to a source/target Exchange Server, the first action (test) performed by the program is always Check connection to Exchange Server, as shown in Fig. 1. below. During this operation, the software tries to access the mailbox of an admin account provided in the previous step of the wizard. If the program cannot connect to your server (Fig. 1.), click the Details link on the right side of the configuration wizard to see more information.

Exchange Migration EWS wizard failure 1
Fig. 1. Failure to connect to source Exchange Server.

Tip

To minimize the risk of connection errors, we advise enabling trust relationship between the source and the target server.

Learn more about creating a forest trust on Windows Server 2008 and newer.

Study the examples below that show the most common server connectivity issues:

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

The error message is produced when the wrong target server administrator account has been chosen, the admin account is not mailbox-enabled, or the admin's SMTP email address is different than its UPN (User Principal Name). You must make sure that provided credentials are the right ones and that they match the UPN. If you are still using the pre-Windows down level logons (DOMAIN\user) you must create a UPN for the purpose of the migration.

The request failed. Unable to connect to the remote server.

This error occurs if the domain name in the administrator's email address is misspelled or the password is wrong. To fix the problem, go to the previous step of the connection wizard and make sure to enter correct credentials. A similar message is also shown if the EWS URL is wrong. In that case, go to the first step of the wizard and enter a correct EWS URL.

Failed to find in Active Directory an email address for [email address].

Exchange Server doesn't support the requested version.

These errors may appear when you choose a source/target Exchange Server version that is not supported by the program. When using EWS connection, CodeTwo Exchange Migration can be used to migrate mailboxes between the following versions of Exchange Servers: 2019, 2016, 2013, 2010 SP1, and SBS 2011.

The request failed. The remote server returned an error: (403) Forbidden.

The error message is produced when there is a problem connecting to the source/target server. Make sure you provided the right name or IP address of the server and the right EWS server address. To check this, you can copy-paste the EWS server address (EWS URL) from the program's settings into your web browser when you are logged in to the source server. If you don't get a credentials request pop-up window, this might mean that you provided wrong EWS server URL or IP.

Account mismatch.

This error informs you that the program has found a conflict with the admin account's ID – used credentials no longer connect to the same environment as previously. This is a security measure that prevents any problems that may occur due to changes made in your source or target environment. Once you receive this error, you will not be able to continue with the migration process (including running Rescan), refresh email addresses or reset the migration state. To fix the problem, you need to reconfigure the source and/or target connection by using new admin credentials (with different UPN / email address) that will allow you to connect to the desired server.

This error is most likely to occur after changing the domain on the source and/or target server This especially applies to the situation where you have transferred the domain from the source server to the target server – the existing source connection might connect to your target server instead. The program also detects if you have deleted the admin account (used previously in the program) on your server and then created a new one, with the same UPN / email address. Such an account will be recognized as a new mailbox (as it has a different GUID) and migrated from scratch (and consume another license) in the program. In case none of the above situations took place and you still want to use the same admin credentials, contact CodeTwo Support.

Failed to connect the exchange Server using the UPN account [email address]. Value cannot be null. Parameter name: uriString

When configuring a connection to your target Exchange server, you may get this error if the program cannot find the admin's email address based on the provided UPN. To fix the problem, go back to the Server connection step, select the Connect to a specific server option, and type the server's FQDN manually. Double check also that the UPN is correct in the Admin account step, especially if entered manually, and continue with the server connection wizard.

Error: (407) Proxy Authentication Required.

Read more about this error in this Knowledge Base article.

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