User Manual

Troubleshooting Common Migration Failures and Errors

Errors may encounter during migration even with the right approach. These may be due to insufficient permissions, invalid credentials, throttling issues etc. The solution for all these hiccups is of high priority.

  • Source or target Connection Failed to Respond

    Reason to failure:

    The Source or target server didn't respond for a particular time period. Usually, this is a time out error. This fails to retrieve a set folder list.

    • This is due to large mailbox, or a large folder associated with a user's mailbox.
    • The Source or target is too slow due to large items count.
    • Due to intermittent network connection server can’t access.

    Ensure that the server is up and running. Try to perform migration again. It migrates the data incrementally without any issues.

  • The Server Cannot Service This Request Right Now

    Reason to failure:

    The Exchange Web Service failed to access the mailboxes due to throttling limits imposed by Exchange.

    • This is due to large mailbox, or a large folder associated with a user's mailbox.
    • The Source or target is too slow due to large items count.
    • Due to intermittent network connection server can’t access.

    Verify, whether the error originated from source server or target server.

    • If you perform migration to or from Exchange 2010 or later, you can disable the throttling policy within the system.
    • If you perform migration to or from Office 365, enable impersonation to minimize the throttling. It can be done using a global admin account.
    • Also, you can contact Microsoft support to disable the throttling.
  • The Remote Server Returned an Error: (404) Not Found

    Reason to failure:
    • Fail to locate a file or resource.
    • Can’t connect to EWS within the environment. Using EdbMails, it is unable to log in to source and target server and migrate the data.
    • Try to connect to EWS with the appropriate URL.
    • The default URL for EWS is usually in the format
    • Try to perform this using a non-domain joined computer which has internet access.
    • Enter appropriate credentials when prompted, you should see an XML document (WSDL)
    • If you have not correctly authenticated the Outlook Web App form, disable it and retry.
    • Ensure that IIS settings are appropriate. Once start the process, go to UI and check again the credentials to rectify the error.
  • SMTP address has no mailbox associated with it

    It is usually related with mailbox migrations to Office 365. EdbMails tries to log in to target server to migrate the data and couldn’t find the mailbox.
    Due to this error, the mailbox can’t be displayed that associated with the SMTP address entered with the EdbMails.


    Sign in to Office 365 admin portal and ensure that a license is assigned to the user having issue; sometimes, it may take time to reflect.

    • If license is not assigned in the admin portal, then there will be no mailbox associated with that SMTP address.
    • EdbMails cannot migrate the data to the target mailbox that has not been provisioned.
  • Unable to Connect to the Remote Server

    A firewall blocks an external traffic, that includes a connection from EdbMails.
    OWA may not be loaded in time.


    If EdbMails application login fails, then verify and allow the EdbMails IP, Port, and executable files in your Firewall. Click the below link for the Firewall settings.

    Check for over-utilization of the network. You could be performing migration of too many mailboxes over the network which requires more bandwidth. Prefer the migration in smaller batches of rectify this.

  • This Account Lacks Permissions to Impersonate Requested User

    EdbMails fails to impersonate the user due to improper permissions on the Admin account.
    This will appear during the impersonation to migrate to Office 365 with a global admin account. EdbMails automatically sets impersonation rights. In some cases it may fail.


    Refer the below link to set the impersonation rights for Office 365 using PowerShell commands / Office 365 GUI.

  • 401 Unauthorized

    This Error is due to:

    • Office 365 account got locked, or password expired
    • Invalid Admin account credentials in EdbMails
    • Insufficient permissions Over-utilization of resources
    • Sign in to the Office 365 admin portal and unlock or change the expired password. Ensure that the account is unlocked.
    • Re-try connection with admin account credentials in the EdbMails application.
    • Reset the proper permissions for the global admin account.

    In case, MFA is enabled in Office 365, then follow the below links to enable MFA and disable security defaults in Office 365.
    Enable MFA in Office 365
    Steps to Enable MFA and to enforce to access from other application
    Disable Security Defaults in Office 365

  • A Specified Object was not found in the store

    This occurs during Exchange migration, when EdbMails couldn’t open the user's mailbox to migrate data.
    It may be due to a permission error over "full access" rights for the admin account.

    • Verify the permissions for the admin account
    • Ensure that the mailbox is not hidden from the global address list
    • Ensure that the mailbox is not having a folder name with a backslash character. Replace with dash and perform re- migration.
    • If you are still facing the issue, contact EdbMails Technical support.
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