Recover a deleted, on-hold mailbox that has been inactive for ore than 30 days - Hybrid Environment

[basitali]

We are in a hybrid environment. A mailbox that was on-hold was deleted and it has been more than 30 days. We restored the deleted account using AD recycle bin. The mailbox won't connect though because it has been more than 30 days.

Have been with Microsoft for the last two days with no resolution. Trying to escalate.

Is there a way to fix this? 

Since the AD account is restored the user alias now exists and the commands for new-mailbox or restore fail because it says the alias already exists. I am trying to NOT create a new account and use the restored AD account to connect to the old mailbox.

I would appreciate any help on this.

[#2]

The old mailbox is likely converted into an "inactive mailbox" now, so you need to follow the process here: https://docs.microsoft.com/en-us/microsoft-365/compliance/recover-an-inactive-mailbox?view=o365-worl...

[#3]

It is a hybrid mailbox with restored AD account so recover command fails with alias already exist @VasilMichev 

[#4]

Try the "restore" process then. https://docs.microsoft.com/en-us/microsoft-365/compliance/restore-an-inactive-mailbox?view=o365-worl...

[#5]

tells me alias already exists

[#6]

there is no point restoring the mailbox to a different address. I want the address so I can set out of office and give live access to mailbox to other users.