Hi @Son2020 ,
According to your description, I found a similar case that mentioned the problem was that the permissions of the Default role assignment policy for a user's mailbox went wrong during migration. The solution is to manually create a new Default policy and assign it to the mailboxes:
New-RoleAssignmentPolicy -Name NewRBAC -Roles
@("MyBaseOptions","MyProfileInformation","MyContactInformation","MyDistributionGroups","MyDistributionGroupMembership","MyVoiceMail","MyTextMessaging","MyRetentionPolicies","My Marketplace Apps","MyTeamMailboxes") -IsDefault:$True
Get-Mailbox <identity> | Set-Mailbox -RoleAssignmentPolicy NewRBAC
Please refer to: Exchange 2016 ECP - "Another user" access broken
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If the above info does not work, please check the following elements:
- By “owa and ecp work”, do you mean the users can directly log in to the ECP page successfully?
- Test whether other administrator accounts have the same results
- Check if you have the same permission on both the problematic database and the Exchange 2013 Database:
Get-MailboxDatabase db01 | get-ADPermission -user [admin01@contoso.com]
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works Thanks!