Proxy Manager 4.0
New in version 4.0 - Proxy Manager can now use OAuth for the M365 mailboxes.
Proxy Manager lets you send emails from Outlook using any alias (proxy) SMTP address with an arbitrary display name from your Exchange account, hosted or on-premises. Outlook 2010, 2013, 2016 and 2019 are supported.
There are no server components, everything is done on the client side - just install Proxy Manager, and you are ready to go! Select one of your proxy addresses and click Send.
All you have to do is specify the SMTP server name and password once. If you are using a hosted Exchange mailbox, Proxy Manager knows how to handle most popular hosting providers, such as Office 365, AppRiver, NetVigour, GoDaddy, etc.. For an on-premises installation, you would need to know the SMTP server name and the password. Proxy Manager will take care of everything else!
When you reply or forward, Proxy Manager detects the address the message was sent to and automatically selects the right sender address on the new outgoing message. Messages sent by Proxy Manager are stored in the Sent Items folder in Outlook, and the non-delivery reports are created in the Inbox. To the end user, it looks like the messages were natively sent by Outlook.