Cannot send e-mail

The server is insecure and unsafe to use. It seems that Mail 8.0 doesn't allow such unsafe authentications. Your best option is to switch to a mail service provider managed by people who know how to do their jobs. If you can't do that, try another mail client, such as Thunderbird.

There was a huge problem with this when Apple changed the OS to lion. I have the same issue with Yosemite now. I can send and receive from the server and all the setting are correct with my ISP. There is another thread that I cannot find that is offering solutions. I had the problem 2 weeks ago and unchecked automatically check and maintain box, save and mail started working. It has just stopped working again, right now. My port is 587....some have changed the port to 25. This is an Apple issue and they refuse to help the people; it is hit or miss. When Lion came out there were 15,000 posts on this same issue and now it is back again.

The server is telling you that it only accepts password logins and that it does not support encrypted connections. That makes it unsafe to use. Unless the service provider has a solution, you should go elsewhere.

Have spent this evening w Apple Support working on what has caused the SMTP servers on all my email accounts to GO OFFLINE, despite me deleting and re-entering all email accounts into Yosemite Apple Mail.

Yosemite Apple Mail/Preferences/Outgoing Mail Server (SMTP)/Click Hold/Edit SMTP Server List/:

See the check box “Automatically detect and maintain account settings” Apple is messing w the Yosemite system setting software to automatically configure all email settings, and further, eliminating email settings for only iCloud messaging.

But Yosemite isn’t getting it right. So one must delete all SMTP servers in this specific window, and add them back, providing addresses and passwords as needed.

After upgrading to Yosemite, I have been unable to use Apple Mail, no matter how many times I DELETE email accounts and re-enter them, plus passwords. Because I was ONLY DELETING IMAP servers. In Yosemite, SMTP servers must be deleted specifically from the above window.

Once I deleted the SMTP servers, then added them back, and rebooted my Yosemite system, Yosemite Apple Mail worked. I can send and receive just like in Mavericks.

Maybe someday APPLE auto configured email will work, or iCloud mail will work automatically, but it’s not there yet.

I don't have any where near the amount of knowledge you have from reading your posts. That said, this is an Apple problem and it seems to happen every time they change their operating system. My server is secure. I am just trying to use logic here....if the problem is as you stated, I would never be able to send e=mail ever. I never have a problem until Apple changes the OS

Barb

Thank you for the step by step and you post is the solution.

Barb

Hi David - I found this thread when I was looking for an answer to the same problem: am with Plusnet and have just done a clean install of Yosemite.

I have several plusnet addresses and the smtp server stayed offline for all of them until, finally, I set up my main account, the one that's myusername@myusername.plus.com. I think that, because all the plusnet addresses use the main account's username and password for smtp, they were blocked from sending until the main account was set up.

Under smtp account information, I have 'plusnet' for description (tho' I don't think it matters what you put there), relay.plus.net for Server Name & None for TLS Cert. In Advanced, 'Automatically detect...' is ticked which puts 25 into the Port box. Use SSL is not ticked. Authentication is Password, username is the main account's username and Password is the main account's password.

Hope this helps you.

You have to ask yourself whether you should be using an email service run by people who can't be bothered to get an SSL certificate to secure their server, or who perhaps don't even know how to do that. That sort of thing might have been acceptable 15 or 20 years ago, but not today.

Having manually deleted and re-entered the SMTP servers and passwords on all three accounts in Yosemite Apple Mail, Mail works beautifully today. You cannot simply delete the email accounts and renter them, because it only deletes the IMAP servers. You must manually delete the SMTP servers and re-enter them plus passwords. Worked for me in Yosemite 10.10.