To begin, open Outlook 2016 and go to preferences.
In the following window, click on the "Accounts" under the "Personal Settings" section.
On the next window, click on "Add Email Account".
You will then see on the next window a place to input your full Pobox email address, or your full personal domain address and click "Continue".
On the next window, input your Pobox account password or your application specific password and click "Add Account".
***If your account is not added and you see an error message stating "Invalid username or password" please see the following screenshots.
Click on "Not IMAP?" in the top right of the window.
Next, click on "IMAP/POP".
Input the following information on in the next window:
Type: IMAP
Email Address: Your full Pobox email address, or your full personal domain address.
Username: Your forwarding address
Password: Your forwarding address account password, or your application specific password
Incoming Server: Incoming server of your forwarding address
Outgoing Server: smtp.pobox.com
Click "Add Account".
If your account was added successfully, then you should see this next screen where you can now click "Done".
You will then be redirected to an overview of your newly added account. You can then verify that your information is correct and begin sending your mail on your newly configured Outlook 2016 client.