Shared Mailbox Access Problems

Question

Users are unable to access shared mailboxes despite having the correct permissions assigned. Attempts to open the shared mailboxes result in access denied errors.

Answer 1

Hi D.56_IT,

Thank you for connecting with us in Microsoft community.

According to your provided description, initially I have found one official document, Can't access a shared mailbox using OWA - Exchange | Microsoft Learn

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Meanwhile, your certain part of scenario should be diagnosed by Microsoft's backend side support team.  Frontline technical support engineer can also involve specific support team for further investigation about some particular situation if it is required. After diagnosing the scenario, our technical support team can provide possible information from their end.

If there are any known issues, this information can be provided by the technical support engineer from their backend resources.

Since we forum moderators have limited permissions and access resources, due to this reason, we are unable to connect Microsoft frontline support team from this public community for further diagnosis.

For the above provided standard process information, in your organization, Office 365 global admin person may need to contact Office 365 support team on backend  via an open service request so they can diagnose this specific scenario through some more technical resources,

For this standard process, here's the official document for the global admin reference: Get support - Microsoft 365 admin | Microsoft Learn****(Online Option).

Note: End-user person may need to contact the Office 365 global admin person in their school / university / Business organization for connecting with technical support engineer for further process.

Important note: If any organization's Office 365 Business/Business/Education subscription is from a syndicated partner or reseller, and if the global admin can't open the service request on their end, they may need to contact the reseller's support provider so they can help the global admin to open the service request on their end. after the Office 365 support team will involve in the created service request.

I hope I have provided all the required process information and direction for your current situation.

Your cooperation precious time is highly appreciated.

Sincerely

Vaidya Darpan