Please ensure that you have followed the correct steps for setting up and executing a mail merge in Outlook. 

Here are some general troubleshooting steps you can try:

1] Verify Data Source: Double-check that your data sources, such as an Excel spreadsheet or a Microsoft Access database, is correctly connected to your mail merge document. Ensure that the data fields in your source file align with the placeholders in your mail merge document.

2] Review Email Account Settings: Confirm that your email account is set up correctly in Outlook and that it is properly configured to send emails. Check the outgoing server settings and ensure that they match the requirements of your email provider.

3] Check Mail Merge Settings: Review the mail merge settings within Outlook to ensure that the appropriate options are selected. Pay close attention to the "Merge to" field, where you should specify the recipients' email addresses.

4] Test with a Sample Document: Create a sample mail merge document with a small number of recipients and test the process. This will help identify if the issue lies with the document, the data source, or the software configuration.

5] Update Outlook and Office: Ensure that you have the latest updates installed for both Outlook and Microsoft Office. Outdated software versions may have compatibility issues or bugs that can affect the mail merge functionality.

6] Disable Add-ins: Temporarily disable any third-party add-ins or plugins that may be interfering with the mail merge process. You can do this by going to the "File" menu in Outlook, selecting "Options," and navigating to the "Add-ins" section.

If the above steps do not resolve the issue, it may be helpful to provide us with more specific details about the problem you are experiencing. Please share any error messages, unexpected behavior, or additional information that could assist us in diagnosing the problem accurately.