Exchange 2019 - EML Viewer for e-discovery

Hello All,

We are running an on premise Exchange 2019 environment.

The Security officer requires to view the messages discovered using E-Discovery on the ECP itself rather than downloading it and viewing it separately which is quite a task as they do for a number of emails..

The issue is that the results are previewable as to the mail subject etc. But when we click on the mail to view, it ends up with 404 PAGE NOT FOUND. Attachment is the final stage screenshot.

Been trying to find a solution, but reaching no-where. What is needed so that I can enable the mail preview on the ECP itself rather than downloading and why do I get this 404 page not found ?

Any leads, solution would be highly appreciated.