setting up email on nopcommerce

hi there
v3.8
just trying to test my site to make sure it will send an email.
I have logged into the admin area and entered my email details / password etc
but i always get the error when sending the test email.

Bad sequence of commands. The server response was: This mail server requires authentication when attempting to send to a non-local e-mail address. Please check your mail client settings or contact your administrator to verify that the domain or address is defined for this server.

Im pretty sure the details are correct and email is working normally but i cant get the nopcommerce site to work with email.

any ideas?
Pretty sure it will be my basic mistake!!

Thanks !

Hi,

Please make sure you have entered / saved correct mailbox credentials.

You may find this helpful: http://www.strivingprogrammers.com/How-to-setup-Contact-Us-form-in-your-nopCommerce-store