In a Microsoft Exchange Server 2013 or Exchange Server 2016 environment, SharePoint discovery administrators are using eDiscovery to search Exchange mailboxes. After the search is completed, the following URL link is provided to allow access for the search result:
https://mysite.domain.com/OWA/integrated/?viewmodel=ItemReadingPaneViewModelPopOutFactory&IsDiscoveryView=1&exsvurl=1&ItemID=ItemID
However, if the Exchange server being accessed is in a different site than where the mailbox server that hosts the data is, you will receive an HTTP 500 error.