Log in to your 4D Web Hosting administrative console at https://members.4dwebhosting.com/ by entering your 'Username', 'Password' and clicking 'Login'.
Click 'MX Records' from the Configuration options.
Replace the top two records with the following:
Click 'Update MX Records'.
The MX records for your domain are updated now. But it may take up to 48 hours for the changes to take effect.