If you are using the secure settings and you are seeing a window pop up that says “Mail can’t verify the identify of the server xxxxxx” then there are two courses of action you can take.
Option 1:
If you're hosted with Xneelo, and the certificate warning comes up, try using the following server name as the incoming and outgoing servers in Apple Mail:
dedi1115.jnb1.host-h.net
Option 2:
Click on Show Certificate. When you get to this screen click on the check box labeled “Always trust “servername” when connecting to “mail server name”.
Next, click on the drop-down arrow where it says TRUST. A security prompt then asks you to type in your computer password.
You will need to make sure that server listed on this message is the correct server. If you know it’s right, then click on “Always trust” next to Secure Sockets layer (SSL).