repeat sending of same email

Question

I created an email to my distribution list. People have told me that they are getting the one email 20-30 time today. I only sent it once

Answer 1

Hi Tom Blaney

I hope you are doing well ! I just want to check if you have had a chance to test the steps earlier? Please let me know if they helped resolve the issue or if you are still experiencing any difficulties. I am here to assist you further.

Best Regards

Answer 2

Dear Tom Blaney

Thank you for reaching out to the Microsoft Q&A forum. I understand you are having problem with a message being sent repeatedly (recipients receiving the same email 20–30 times) from Outlook on Windows (classic) after you sent it once. Please follow these steps:  

• Isolate add-ins/customizations  
  • Start Outlook in Safe Mode (Safe Mode disables add-ins). 
  • Right-click Start > Run, type: Outlook.exe /safe, then OK. 
  • If the repeated sending stops in Safe Mode, the cause is likely something loaded in normal mode. Please continue with Step 2 and Step 3 below. 
• Rebuild the Outlook profile  
  • Create a new Outlook profile using Create an Outlook profile - Microsoft Support:. Use the profile picker (hold Shift while starting Outlook) or Run: Outlook.exe /profiles, then create a new profile and add the account again. Then test sending a single email to yourself first (not the full distribution list) to confirm normal behavior before sending broadly.  
• Repair the Office/Outlook installation  
  • Use Repair an Office application - Microsoft Support steps (this repairs the whole Office suite, including Outlook):  Windows Settings > Apps/Apps and Features > select Microsoft 365/Office > Modify > run Quick Repair; if still failing, run Online Repair.  
• When the above does not resolve it   
• Visit Contact - Microsoft Support     
• Type a brief description of your issue in the search box    
• Scroll down to the bottom > select Sign in to contact support    
• Log in to your personal Microsoft account.     
• Under Products & Services, select "Other Products"; Under Categories, select a suitable Category.   
• Click "Chat with a support agent in your web browser" (during business hours) 

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Answer 3

If your distribution list recipients are receiving the same email multiple times, it could be due to several reasons:

1. Email Duplication: If you are using a system that has email deduplication features, ensure that it is enabled. When deduplication is enabled, the system should only send one email to each unique address. If it is disabled, the email may be sent to each contact in the distribution list multiple times.
2. Rate Limiting: If the email system has rate limits and you exceed them, it might cause unexpected behavior in how emails are sent or received. Check if your email address has been temporarily rate limited.
3. Distribution List Configuration: Ensure that the distribution list is configured correctly and that there are no duplicate entries within the list itself.
4. Client Issues: Sometimes, client-side issues in Outlook can cause emails to be sent multiple times. Check for any errors or issues in the Outlook application that might be causing this behavior.

To troubleshoot this issue, consider reviewing the settings of your distribution list and any relevant email sending configurations to ensure everything is set up correctly.

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References:

• Best Practices when sending email
• Errors when sending emails from security groups, distribution lists, or mail-enabled Public Folders in Outlook for Mac