Data migration service error codes

To resolve this, consult your Exchange documentation to fix the corrupted folder. Then, verify the steps in Migrating from an EWS environment .

To resolve this, consult your Exchange documentation to fix the corrupted data. Then, verify the steps in Migrating from an EWS environment .

• The service account running the Exchange Web Services (EWS) application pool is set up incorrectly.
• EWS can't talk to the directory.
• A trust between forests is set up incorrectly.

Try the troubleshooting steps in Migrating from an EWS environment .

Internal server error. This error is usually temporary.

If the issue persists, it could mean that the data migration service is operating at a rate that exceeds the limits of the source system. To resolve this issue, adjust the migration speed . Make sure the source server can handle the number of connections you select.

The issue is usually temporary. 

Exit and restart the migration.

Failed to open the IMAP folder. Check Google IP address ranges for outbound mail servers and ensure that the IMAP server can accept a connection from them. If required, see the additional setup steps for migrations from HCL Domino or Gmail . Then, ensure all of the folders in the affected source user's mailbox can be accessed using IMAP. To verify this, use an IMAP mail client such as Mozilla Thunderbird or Apple Mail.

Can occur when migrating from Gmail or Google Workspace and a Gmail label on the source account contains unsupported Unicode characters, including Ideographic spaces and no-break spaces.

Before migrating, rename any affected labels on the source account. Post-migration, revert back to the original name in both the source and target mailboxes.

The default personal namespace of the user is set incorrectly.

To check the personal namespace:

1. Sign in to your IMAP server using an SSL protocol toolkit, such as OpenSSL.
2. Sign in to the source user account.
3. Enter a namespace command to check the namespace configuration.

   Example: A001 NAMESPACE

For more information, consult the Internet Engineering Task Force documentation on IMAP4 namespace and your IMAP server documentation.

You might see this error if:

• Your IMAP credentials are invalid. Check the username and password and try again.
• A user account in the source domain is suspended. Restore the user account and try again. For details, go to  Restore a suspended user .

If the issue persists, choose an option, depending on where you're migrating from:

• I'm migrating from an existing Google Workspace account:
  1. Verify you completed the setup steps for existing Google Workspace accounts .
  2. If the issue persists or you use 2-Step Verification, you can migrate data as if you’re migrating from Gmail.

     For details, go to Set up & migrate from Gmail (and, if needed, try the troubleshooting step below for Gmail).

• I'm migrating from a personal Gmail account (ends with @gmail.com):
  1. Verify you completed the preparation steps for Gmail .
  2. If the issue persists, follow the steps for error code 18020.
• If you're migrating from another IMAP provider, check with your service provider or system administrator.

The connection to Gmail using IMAP failed.

The source account requires a more secure form of authentication because it has 2-Step Verification enabled. To migrate using more secure authentication:

1. Exit the migration.

   For steps, go to Pause, cancel, or exit a migration .

2. Start the migration again, selecting Gmailas the migration source.
3. Add the source account and follow the instructions to authorize access.

If it's not possible for you to take the steps above, create an App Password in the source account. Use it instead of your regular password when adding the source account in the data migration service. For details, go to Sign in using app passwords .

Note:The data migration service doesn't require you to turn off 2-Step Verification or allow access to less secure apps.

Events didn't migrate because the participant isn't an attendee or organizer of the event. To troubleshoot this issue:

• Check the ICS file from the source account and make sure the migrated user is a participant of the event.
• Check if the user has aliases on the source server that don't exist in Google Workspace. If the aliases are missing, add them to Google Workspace.