Airmail 2 can't send emails

I am using Airmail 2 and when I try to send a libre file via email I get a error message Unable to find a working e-mail configuration. I am using OS.10.10 on my MacBook Air.

With 10.10 I can’t find the library to set up the email function

I am afraid that you are in the wrong forum. This here is for LibreOffice and not for Airmail 2 of Mac OS.