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For better research, please provide more details about this case:
Are all messages for this user delayed for the same amount of time?
What type of account are you using? Is it a outlook.com account or an Office365 account?
Here are some of the steps you can try to troubleshoot the email delay issue:
- You can sign in to your web mail to have a test for receiving emails and check if the delay still occurs. If the problem not happened in the web, please try to repair your Outlook Client.
- Check if the sender has enabled the delay delivery option in Outlook. This option allows the sender to specify a date and time for the message to be sent. You can ask the sender to verify this setting and disable it if needed. For more information about how to use this option, please see Delay or schedule sending email messages.
- Contact your admin in your organization and ask them to use the message trace feature in the Security & Compliance Center. This feature can help you find out the status and details of the email delivery process. More information, see Message trace in the Security & Compliance Center.
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