Sending Mail

[#1]

I’m using Mac Mail V9.1, having upgraded to El Capitan, and cannot send mail. The outgoing server is shown as ‘(offline)’.
The online guide is dated 2012. Where is Nov 2015? What's there does not correspond to what I have.
I’d like to send mail using any ISP but the web help doesn’t.

[#2]

The settings are fundamentally the same, irrespective of the client.
If you look at the attached settings dialogue, make sure you have all three of the following options disabled:

• Automatically detect and maintain account settings


• Use SSL


• Allow insecure authenticator