Mail can't connect to SMTP server for IMAP accounts

Port 25 is not considered a secure port.You need to use different settings to connect in a more secure manner.

• "Incoming Mail Server Info", "Mail Server": "mail.example.com", "User Name": enter full email address
• Under the "Advanced" tab, "IMAP Path Prefix" is "INBOX", "Use SSL" is checked, and the port is "993". "Authentication" should be "Password". "Automatically detect and maintain account settings" should be unchecked.
• Outgoing Mail Server Info", use {"SMTP Server": "mail.example.com", "User Name": enter full email address
• "Edit SMTP Server List…use SSL port "587", password authentication, and the full email address for the username and the appropriate password.

Hi Scott,

I had sort of the same issues but it was only with sending. I could receive messages just fine but not send. I know this might sound stupid but try re-entering your password on your accounts then re-start mail. It took a couple tries but it got my IMAP email account working. Hope this will work or at least aid in some way.

-Crazy

This this to fix repeated password requests....

Open Keychain Access in Applications/Utilities

Search for your Dreamhost accounts. There should be two entries (incoming, outgoing) for each account.

It's not uncommon to find old entries. You might want to delete all and start clean.The Keychain isn't smart and will keep all old entries when you add/change a password.

While you are in the Keychain run Keychain First Aid, Under Keychain Access in the Menu bar.

Open Mail

Open Connection Doctor.

If you see red for the account, enter the password again.

If you continue to have problems, delete the account then add it back.

I had the precise issue in the original post: could not send email despite multiple SMPT settings.

I went into Keychain and eliminated all references to the accounts I was experiencing difficulties with, restarted, opened Mail, and was prompted to enter my password twice (once for incoming, once for outgoing).

Problem solved.

Apparently Keychain corruption/confusion was the culprit in my case.

Thanks Diane for the pointer. I was pulling out what was left of my hair.

Glad that solved your problem. 🙂

Like musQaria this caused me hours of frustration. I tried all the tricks, such as deleting the keychain passwords, removing the certificates then accepting then again and so forth. Connection doctor simply times out. I used the setting on the dreamhost wiki.

Eventually we resolved it.

I am convinced the problem was cause by dreahnost blocking my IP address.

This probably happened because we had several OSX devices whit the same accounts on our home network, some of them were old and had not had the email password updated. After several failed attempts to login DH would block our public IP. While I don't have a fixed IP the problem would go away when our IPS issued our modem a new IP but appear again if some one opend up mail on an old ipod on the network that had a bad mail account setup or we were re-issued with an already blocked IP

Eventually after some time all the IP addresses in my ISPs modem pool were blocked and we almost always were issued the same IP by the ISP

I only discovered this after re-creating the account from scratch on a new device then being lucky enough to get a new IP after restarting the modem. It seemed that the login error response from DH would only be given for a short time after the IP was first blocked after that it would simple fail to connect and time out with no error message.

We had 10 different OSX mail devices each with 1 or 2 mail accounts on them used by different family members.

DH took around 24h to respond and did so by email so we had no easy way of communicating whit them and were with out email for about 5 days.

eventually we found an old ipod touch with mail setup on it that was probably responsible for all the failed stmp login attempts.

Quite frustrating.

This was the first helpful answer I have found after searching everywhere. I posted a question over in El Capitan/mail. I get emails from Google about somebody trying to access my account. I look in the logs at that time and see

[IMAP] Got Error Domain=MCMailErrorDomain Code=1030 "The IMAP command “AUTHENTICATE” failed with server error: (#AUTH903) Missing 'user' field in the provided XOAuth2 authentication payload." Then XOAUTH2 requires user.

I'll try the settings and see what happens.

I suggest you also setup two step authentication. When you enable 2-Step Verification (also known as two-factor authentication), you add an extra layer of security to your account. You sign in with something you know (your password) and something you have (a code sent to your phone).

https://support.google.com/accounts/answer/185839