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A cloud-based service included in Microsoft 365, delivering scalable messaging and collaboration features with simplified management and automatic updates.
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Hi Thomas,
Good day and thank you for providing such a detailed description of the issue and for outlining the extensive troubleshooting that has already been performed.
Based on the information you've shared, it does appear that the problem may be specific to the way New Outlook is rendering messages within certain shared mailboxes. The fact that:
- The email list loads normally
- Messages can still be opened successfully in a separate window
- Outlook on the web displays the same messages correctly
- The same message renders properly after being moved to another mailbox
- Common troubleshooting steps have already been performed without resolving the issue
This may suggest that the message content itself is not corrupted and that the behavior may be related to how New Outlook is processing or rendering content within certain shared mailboxes. Additionally, considering that other users have recently reported similar symptoms, this may require further investigation from Microsoft Support. In this case, the best next step is to have your Microsoft 365 administrator open a support request through the Microsoft 365 Admin Center.
A technical support engineer can then initiate a remote session, review backend settings, and run diagnostics. If needed, they can escalate the case to specialized engineering teams who are well-equipped to perform advanced troubleshooting and provide targeted solutions.
As moderators, our primary goal is to provide helpful guidance and support through general troubleshooting steps. While we don’t have access to internal systems or administrative tools required to resolve account-specific or backend issues, we truly appreciate your understanding of these limitations. We genuinely hope the information we share helps point you in the right direction, and we're always here to assist as much as we can within our scope.
For guidance on how to request support in the admin center, please share this with your admin: Get support - Microsoft 365 admin.
Additionally, your administrator may also use the Report an issue option within the Microsoft 365 Admin Center > Service health > Overview > Report an issue to submit feedback and diagnostic information directly to Microsoft, as this may help provide additional data for investigation.
In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support.
I hope this information is helpful. Please feel free to reach out if you need further assistance.
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