When attempting to test Autodiscover using their user account credentials from an Exchange Management Shell using the Test-WebServicesConnectivity command, the autodiscover test completed successfully. This brought it down to an issue with the end workstation, not the server, user account or mailbox.
The error which was experienced when performing an Autodiscover attempt in "Test E-mail AutoConfiguration" was:
Autodiscover to https://EXCHANGESERVER.DOMAIN/Autodiscover/Autodiscover.xml Failed (0x800710DD)
This is shown in the following screenshot:
After diagnosing the problem it turns out that this issue was caused by a proxy server configured on the end workstation. Disabling the proxy server resolved the issue.
As a permanent solution, the proxy server must remain enabled. To ensure the Exchange server is not used via the proxy, you can add the Exchange server as an exception.