How to connect to GMail
Gmail requires establishing secure connections (SSL/TLS). WebMail Lite supports SSL/TLS and can connect to Gmail.
If you're willing to log into Gmail accounts directly, add gmail.com domain in AdminPanel and make sure the following mail server details are supplied:
* Incoming mail: imap.gmail.com
* Outgoing mail: smtp.gmail.com
You also need to make sure IMAP access is allowed in your Gmail account configuration, see "Forwarding and POP/IMAP" section of account settings.
NB: by default, Gmail only allows IMAP/SMTP access if you authenticate via OAuth 2.0. To make username/password authentication work, you'll need to allow less secure apps to access your account. It might also be necessary to enable account access from every new IP address.
Note that, despite the name, allowing access for less secure apps doesn't actually reduce your account security. For example, if you access Gmail with Microsoft Outlook or Mozilla Thunderbird, Google treats that as insecure, just like any other kind of username/password authentication.