Q: Why does my mail app continuously go offline since upgrading to El Capitan?

I recently purchased a new Macbook Pro - 3 weeks ago, and I have a recurring issue in that the mail app repeatedly goes offline while I have a solid connection to the wifi, and internet. I upgraded to El Capitan, and still have the same issue.

I've removed all in iCloud settings 3x and still the same problem.

thanks!!