Troubleshooting server connection

No matter if you configure EWS connection to source Exchange Server or to source/target Office 365, the first action (test) performed by the program is always checking connection to your source server (Exchange Server, as shown in Fig. 1., or Office 365). During this operation, the software tries to access the source administrator's mailbox.

Exchange Migration actions EWS
Fig. 1. Actions performed when connecting to a source Exchange Server via EWS. The configuration window for source/target connection to Office 365 looks similar.

If the result is negative (Fig. 2.), click on the Details link on the right to see more information.

Exchange Migration EWS wizard failure 1
Fig. 2. Failure to connect to source Exchange Server. This error looks similar for source/target connection to Office 365.

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 either the wrong target server administrator account has been chosen or the email address is different than the 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.

  • 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.

  • Error: (407) Proxy Authentication Required.

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.

  • The Autodiscover service couldn't be located.

There may be a few reasons for this error to occur. If you recently added/migrated a domain the simplest solution would be changing the email address of admin account you are using (in Exchange options on Office 365) back to <yourdomain>.onmicrosoft.com. The other reason may be that your domain is not yet registered/verified with Microsoft's DNS or there is a problem with the Global Administrator account on Office 365 that is being used with our program. We recommend either checking the domain registration status, contacting the Microsoft Office 365 Support or trying the universal solution below:

  1. Choose a different existing account or create a new account on Office 365.
  2. Make sure the account is fully mailbox enabled, i.e.:
    • Log in to OWA 365 with this account’s credentials.
    • Set the regional settings if prompted to do so.
    • Send an email to yourself or to another account and confirm it was delivered.
  3. Assign the Global administrator role in Office 365 to this account.
  4. Add Impersonation Rights for this account. If you have problems doing that from within our software please do it manually following steps for Exchange Online from this article.
  5. Use this new account in our program.

If the above does not help consider:

  • running the software on a different machine – this way you will rule out problems caused by security settings on the original machine, e.g. firewall;
  • installing the software outside of your environment (forest), e.g. on a virtual machine with trial Exchange Server, at home – this way you will rule out problems caused by customized or even improper DNS, proxy or routing configuration.
  • The SSL certificate could not be checked for revocation. The server used to check for revocation might be unreachable.

The program is unable to check whether your Office 365 SSL certificate is still valid or not. As per this Microsoft article, this issue is usually related to network connectivity problems. It may also be caused by other factors, for example problems on the certificate revocation list provider side. The solution may involve:

  • making sure your computer has perfect Internet connection;
  • waiting an hour or so before trying again to rule out the temporary network problems of 3rd parties;
  • running the software on another machine to rule out any particular machine limitations, network security issues, network settings, etc.

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