For the second time over the last few months outgoing e-mail is stuck in the Outbox. The first time, the mail eventually was sent after a day. Now it is two days with nothing happening. I am using att e-mail and a POP server running Sierra 10.11 on a Mac.
iMac 21.5", OS X 10.11
To test your settings, use Connection Doctor.
If you can receive mail but can't send mail permanently (not transiently), then your SMTP server settings are likely incorrect.
Mail has two sets of credentials. One set for receiving and reading mail via POP or IMAP, and a second set for sending via SMTP or ESMTP. Each of the two sets of credentials has a user and password and server name, an SSL/TLS setting, ports, and some related details.
To test your settings, use Connection Doctor.
If you can receive mail but can't send mail permanently (not transiently), then your SMTP server settings are likely incorrect.
Mail has two sets of credentials. One set for receiving and reading mail via POP or IMAP, and a second set for sending via SMTP or ESMTP. Each of the two sets of credentials has a user and password and server name, an SSL/TLS setting, ports, and some related details.
In addition to MrHoffman's excellent commentary, when sending email (as he mentioned) this will be a communication between your Mac and your email provider's SMTP server. However, the first thing that your Apple Mail client will do is perform a DNS lookup for that server.
With that said, there also may be an issue with either the DNS server(s) that you are using or with the DNS server settings on your Mac. One quick test would be to try sending emails from outside your network ... unfortunately, since you have a desktop Mac, that wouldn't be practical.
By default, your Mac is probably using your ISP's DNS servers or pointing to your local network router (which is basically the same thing.) What you can try is use another set of DNS servers, like those from Google or from OpenDNS, to see if that can help.
If the mail eventually leaves the outbox, then your router is offline, your ISP is offline, or your network connection is otherwise intermittent, or the usually-ISP-provided DNS setting is wrong. You can try rebooting your router, as that can clear some of the common issues. If you manage your router and not your ISP, check the router firmware revision with the router vendor.
To check locally installed software, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor. Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply Pastebin
If the credentials are working as indicated by Connection Doctor, then either the mail account has been taken offline, or there's an intermittent connection problem. Or there's some locally-installed software that is doing something... unexpected.
I looked at Connection Doctor which indicated that connection and log in to all of my servers was OK. In the Mail Preferences settings there is a password required for the POP server but not for the outgoing mail server which is simply listed as Att. One other piece of information is that I have no problem sending e-mails with my att account on my i Pad.
I have other ways to send e-mails so this is a matter of convenience more than anything else, but I would like to get to the source of the problem. Thanks to you and Tesserax for taking the time to help with with this.
The strange thing is that I am getting new e-mails I just can't send. Does this shed any light on the problem?
My next step will be to take my computer to the geniuses at the Apple Store to look into the problem. If they can diagnose it I will post the solution.
Found out Genius Bar no longer exists but can get Apple help on the phone (no cost). Took 45 min to diagnose/solve the problem but the root cause was new ATT email server ID's which I was not notified about. Changing all the settings in the mail preferences solved the problem.
Outgoing Mail Stuck in Outbox
