How to configure Outlook and later to use ActiveSync

Before you complete these steps you have to activate ActiveSync on your POP account. Refer to this knowledge base article for details.

By default, ActiveSync cannot be set up on Outlook 2016, 2019 and Outlook for Office 365 because it is now using Autodiscover for Exchange.  However, it is possible to make a registry update to disable Simplified Account Creation to use ActiveSync on newer versions of Outlook, details after the link:  https://support.microsoft.com/en-us/help/3189194/how-to-disable-simplified-account-creation-in-outlook  
 
To configure Outlook to connect to our email server via ActiveSync:
  1. Open Outlook and go to File > Info > Account Settings.
  2. Click "New."
  3. Choose "Manual setup or additional server types" and click "Next."
  4. Choose "Outlook.com or Exchange ActiveSync compatible service" and click "Next."
  5. Enter a unique name in the "Your Name" text box.
  6. Enter the full email address of your POP account.
  7. Enter the POP3 mail server name (example: m0#.internetmailserver.net). Replaced # with your email server number. To get this information. Log into the control panel. Click on Sites > Site account > Email Manager Icon. See Email Information.
  8. Enter the full email address in the "User Name" text box.
  9. Enter the password of the POP account in the "Password" text box.
  10. Check "Remember Password".
  11. Click "Next."
You may get a certificate warning after the first initial setup. You can ignore this warning and complete the installation.