Error Message

Event ID: 3460
The Task 'Exchange Mailbox Archiving Task for EX01' failed to log on to Exchange server 'EX01' using mailbox 'SMTP:svc-ev@domain.com'.
Check that the mailbox has not been hidden, that the server is running and that the vault service account has sufficient permissions on the server.
Enterprise Vault used the following settings for the Outlook Anywhere connection to Exchange 2013 or later:
Proxy server: 'webmail.domain.com'
Requires SSL: 'True'
Certificate principal: 'msstd:webmail.domain.com'

Event ID: 2256 The Archiving Task 'Exchange Mailbox Archiving Task for EX01' could not be started due to startup errors.

Dtrace of the archive task shows below error:

EV:H {CMailboxHelper::CreateProfileAndSessionEx} (Exit) Status: [ClassFactory cannot supply requested class (0x80040111)]
EV:M {CMailboxHelper::CreateProfileAndSessionAndOpenMailbox:#1227} Failed to create profile and session for server Exch01
EV:M {CMailboxHelper::CreateProfileAndSessionAndOpenMailbox:#1228} Error being returned : 0x80040111
EV:H {CMAPISession::CreateMapiSession} (Exit) Status: [ClassFactory cannot supply requested class (0x80040111)]
EV:H {CAgentTask::Initialise:#1347} Failed to open privileged MAPI session: [0x80040111]. Aborting agent startup.

On the Enterprise Vault (EV) server, upon manually configuring the Outlook profile for system mailbox, it shows a credential prompt wherein an attempt is made by Outlook to connect with Office365 Endpoint for Autodiscovery.

Ideally, the Autodiscovery request should be sent to the Exchange On-Premises directly.
 

Add the following registry key on the EV server to stop Outlook from checking Office365 Endpoint for Autodiscovery:

Name - ExcludeExplicitO365Endpoint
Path - HKEY_CURRENT_USER\SOFTWARE\Microsoft\office\XX.0\outlook\autodiscover
Type - DWORD
Value = 1

Delete any existing Outlook profiles and then restart the EV server. 

Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes.