Q: I can receive emails but suddenly cannot send.
I can receive emails but suddenly cannot send. I get an authentication rejected message. It appears to have started after I upgraded to El Capitan. At that time I lost all of my emails but they reappeared a couple of weeks later. Why can't I send emails? Once I put them in a folder I can't access them from Xfinity so I can't go there to reply.
MacBook Air (13-inch Mid 2012), OS X El Capitan (10.11.2)
Posted on Dec 29, 2015 5:15 AM
Use the Mail Connection Doctor to make sure that your SMTP server settings are correct.
SMTP stands for Simple Mail Transfer Protocol but if you want an easy way to remember what it does--Send Mail To People.
Mail (El Capitan): Use Connection Doctor
You can try using the mail lookup tool to check for the correct mail settings. Sometimes e-mail service providers change their settings without telling Apple so the Apple software can be updated.
https://www.apple.com/support/mail-settings-lookup/
If Apple does not have settings for your e-mail service provider, that means your e-mail service provider did not give them to Apple. If that is the case, you will need to contact them and ask for the correct SMTP server settings.
Mail settings you might need from your email provider - Apple Support
Posted on Dec 29, 2015 7:17 AM