After configuring a Gmail account and inbox and configuring HEAT to use them as the email listener and outbound SMTP server appear, errors are generated on both inbound and outbound processes even though the mailbox and server appear to be configured correctly in the HEAT application,
The core error on outbound email:
System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required.
The core error when attempting to fetch inbound email:
There are account and inbox settings on the Gmail side that need to be set in order to connect successfully.
When using IMAP4 as the Protocol for the incoming email listener, the following setting must be enabled:
Log into the Gmail account (mail.google.com)
Select the Gear icon in the upper right and choose 'Settings'
Select the 'Forwarding and POP/IMAP' tab
Select 'Enable IMAP'
(Note: if using POP, enable the appropriate POP setting on this tab.)
For outbound (and functionality) to work, the following account setting must also be enabled:
Select the Account icon in the very top right (by default will display the first letter of the account name in a circle)
Select 'Sign In & Security'
Select 'Connected Apps and Sites'
Set 'Allow Less Secure Apps' to ON