In order to send/receive mails through EGroupware, the mail settings for the user should be updated from Home -> eMail -> Admin section -> Site configuration (located at the bottom left corner). The exact details which should be set for a mail profile are as follows:

--Global section:

    "Profile access rights setting" should be set to the user which will use the mail profile in question.

--SMTP section:

    SMTP server type: Standard SMTP server
   
    SMTP server hostname or IP address: Domain.com or Server's Hostname
    SMTP server port: 25 or 2525

    Use SMTP auth: ticked
    Send using this eMail-Address: e-mail address from which the messages will be sent
    Username: please use the whole e-mail address as username
    Password: the correct password for the e-mail in use

--IMAP section:

    IMAP server type : Standard IMAP server

    IMAP server hostname or ip address: Domain.com or Server's Hostname
    IMAP server port: 143
    IMAP server login type:  Username/Password defined by Admin

    Username: please use the whole e-mail address as username
    Password: the correct password for the e-mail in use

    Encrypted connection: no encryption
    Do not validate certificate: ticked

It is recommended to create a separate profile for each EGroupware user.