Load balancing failed to find a valid mailbox database. error

Question

I'm adding a new mailbox. I click Existing user. Selecting a user I click save  

i use DAG I can choose base itself. but then an error occurs

owa too not open X-ClientId: 9DBD1C75698E40849C5C55AD660A1B4A request-id 1cccbb15-a3a6-4e53-9dfa-8442f38893e2 X-OWA-Error Microsoft.Exchange.Data.Storage.UserHasNoMailboxException X-OWA-Version 15.2.1258.28 X-FEServer NODE4 X-BEServer NODE4 Date:20.02.2024 8:49:25

Answer 1

Hello @Sergey,

According to the error message you provided, this Error "Load balancing failed to find a valid mailbox database" usually occurs when enabling or creating a mailbox. The possible solution is to modify the parameters. First, as you posted, you need to run the Get-MailboxDatabase -Identity "<mailbox database>" | Format-List Name,IsExcludedFrom*,IsSuspended* command to determine whether the database is locked. If the result shows True, you could change the setting to False by running Set-MailboxDatabase "<mailbox database>" -<parameter> $false. Also, remember to always keep your Exchange Server up to date and make sure you have any Exchange Server cumulative updates installed.

​About owa is also not open and Microsoft.Exchange.Data.Storage.UserHasNoMailboxException occurs, this error may occur if the user's mailbox setup is not completed, and if the license has just been assigned to this user, it may take more time to mailbox set up. Alternatively, if the problem persists, you could try disabling and re-enabling OWA for your mailbox, clearing cache, reopening the browser and logging in again.

Hope the above information is helpful to you!

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Answer 2

Double-check the creation: Did you complete the mailbox creation process, including enabling and assigning a license?

Verify the database: Are you using the correct database or DAG when creating the mailbox?

Wait for replication: Allow time for changes to be replicated across all servers in your DAG. Check for server problems using the Get-MailboxDatabaseCopyStatus and Get-MailboxAvailabilityGroupNetwork cmdlets.

Confirm AD replication: Ensure that Active Directory replication has completed (repadmin /showrepl).

Disable third-party tools: To avoid conflicts, temporarily disable any that are in use. 

For more information - Load balancing failed to find a valid mailbox database.

If the issue persists, seek help from an Exchange expert.

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