Give 365 user access to on prem shared mailbox

[asolano1400]

Ok so here's the scenario.

• Hybrid Environment.
• User is in the cloud.
• Shared mailbox is on premise.

We need to allow the cloud user to have access to the shared mailboxes on prem. I've added the permission to the cloud user. But it's not showing up. Even tried to add it manually. And it says that it cannot find the mailbox.

Any ideas?

[#2]

Cross-premises permissions are only supported in specific scenarios, and need some prerequisites. Read here: https://learn.microsoft.com/en-us/exchange/permissions#mailbox-permissions-in-hybrid-environments
https://learn.microsoft.com/en-us/exchange/troubleshoot/send-emails/overview-delegation-office-365-h...

[#3]

@Vasil Michev So that didn't really help. According to that article. The user should be able to see the on prem shared mailbox. However he is not currently able to. Is there a way to check his permissions in via online powershell?