![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(297.6, 14.000000000000002%, 38%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EJK%3C/text%3E%3C/svg%3E)
Exchange | Exchange Server | Management
The administration and maintenance of Microsoft Exchange Server to ensure secure, reliable, and efficient email and collaboration services across an organization.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(25.6, 67%, 12%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EJS%3C/text%3E%3C/svg%3E)
What changes have been made to your environment recently may related to this issue? Do all the people in your organization meet this issue when accessing OWA?
Are you accessing your own mailbox owa or trying to open other users emails?
If you are going to access other's mailbox, please make sure you have been assigned right permission to perform the action.
In addition, are you a domain admin or org admin? If you are, they are specifically denied access to open other users mailboxes. As is best practice, I would recommend creating a separate admin account for administrative access and a regular user account for normal user stuff.
You could refer to this thread discussed about this issue as well: Can not access other users mailbox
If the response is helpful, please click "Accept Answer" and upvote it.