If one of your accounts seems to be misbehaving (it may not be sending email, seem inactive or in other ways seem faulty), launch Mail Preferences and select the account in the Accounts tab, then click on the ‘Advanced’ tab. This fix seemed to help when OS 10.10.4 shipped earlier this year, so it seems worth trying in OS X El Capitan.
If you can’t send email using your iCloud account after upgrading to El Capitan then following these steps may help: VerifyĪpple offers a simple online tool to verify your email settings so you can ensure they’re set correctly in Mail.
If you’ve been suffering problems using Outlook with El Capitan, then you should download the latest software patch released by Microsoft last week.
You can also explore some of Mail's hardest to find controls in this article here.
