Hi,
By default the retention period of the message tracking log is 30 days, you can check your retention period by Get-TransportService | ft Name, MessageTrackingLogMaxAge command, if it is 30.00:00:00, unfortunately, I'm sorry to tell you that you can't view the message tracking log older than 30 days.
Here is a screenshot of the test I did on this command:
If you want to modify the retention period, you can use Set-TransportService. For example:Set-TransportService -Identity ex19 -MessageTrackingLogMaxAge "365.00:00:00"
Hope this helps!