Q: El Capitan - Mailproblems

Have the same issues here--and know the settings are OK (have another Mac running Yosemite and an iPhone on iOS9 working fine). Have tried the usual things such as logging out and restarting, but still no resolution, even after trying (unsuccessfully) to reenter the passwords).

What worked for me is to delete the mail account (I'm chicken so I just unchecked the box for mail) and then create a new mail account with identical settings. Once that works, you can delete the old account.

I've got the same problem.

all my mail accounts can receive mails but i can't send any mail.

i closed ssl on all acconts and saved the settings. after reopen the settings ssl is on again.

when i try to send a mail, mail asked for a password from another account. when i put in the passwort the i became the answer mail that the authorisation failed. when i check the connectio,n mail connect to the server and for all accounts the green lamp is on, all account- and passwordsettings are correct! BUT I CAN'T SEND ANY MAIL

Maybe any idea?

i must send mails with layouts to customers.

Hmm...

I'm still having issues, as well. Right now, would it be possible to access your mail via a Web interface?

Also:

From my research on other boards (Ask Different, et.al.), one thing you may want to check is your outgoing mail server (and port number, if it's SSL). According to some developers who were testing the beta versions of El Capitan, the problem may be the result of Yosemite allowing some more room for error, which is no longer allowed (presumably for security reasons).

Another temporary solution is to use a third-party mail client such as Thunderbird or Outlook. Because of redundancy, I have a separate Web server account (with associated e-mails), where I use Thunderbird as the client. No issues at all on this setup after upgrading to El Capitan. If you're accessing via the IMAP protocol, it won't pull all the messages anyway--those will be on the server still (unless you delete them), so you can do this until the issues in Apple Mail are resolved.

Update--

I have my issues worked out. As noted in my post above, some settings that may have worked in the past (incoming mail server, outgoing, port numbers, et.al.) possibly won't now.

It can be confusing to find some of these settings. What you could try, is like LRicci posted above, deleting your accounts and setting them up by going in the Apple Mail menu > Accounts. After that, you can check your advanced settings by going to main menu > Preferences. Make sure all settings are correct (you may have to confirm with your Web/Mail hosting provider).

Alright, here is what I figured out if you are using Time Warner (I used LRicci's method from above):

1) Make sure you can access Webmail online.

2) Contact TW and get all of your account information for the POP servers and the IMAP servers

• incoming address and port number
• outgoing address and port number
• username should be email address
• password is the same for both online webmail and Mac Mail client

3) WITHOUT deleting your non-functioning email yet, create another email;

• for me, my POP email client was not working so I created an another IMAP (automatically chose this for me)

1. Open Mail
2. Click on 'Mail' next to the Apple in the upper left hand corner
3. Click on 'Preferences'
4. Click on 'Accounts'
5. Click on the '+" at the bottom left hand of the small window that opened when you opened 'Accounts'
6. Click the 'other' radio button
7. Put in username and password that you used to access webmail and your Mail Client.
8. Click 'sign' in.
9. Enter information as needed that you got from TW.

4) NOTE : Incoming port number was incorrect at creation point and had to be altered using the TW information.  Changed it and just checked it but it switched

    back to the information that originally was created when creating a new account.  Weird, huh?

5) If you are nervous about deleting old email (in my case, it was the POP client), just click the box to make it inactive.

6) Send and receive email again through Mac Mail.

Hope this helps,

Chuck

Before you delete your old e-mail account, make sure you have an offline archive of the messages you want to keep. By default, POP accounts delete messages from the mail server when loaded by your mail client.

For IMAP accounts, messages are stored on the mail server until deleted, per your account settings.

Not sure what would happen if I deleted POP account, that is why I just made in "inactive" or "not enabled".

As of now, with my solution my Mail is functioning properly.

I changed the outgoing mail port to 465;  fixed issue.

THANK YOU!!  Worked like a champ for me when my Exchange e-mail account kept causing it to crash!

I ahve an account setup that I can access online and the passwords and usernames work there. I did what was suggested and deleted my account and then tried to add it again. I didn't get past the first dialog without getting an error because "Unable to verify account name or password". Does anybody know why this is happening?

Same for me. Installed El Capitan because thought Apple would have learnt from the Yosemite problems, but No.

Immediately lost access to Exchange email account and find my four email account servers are all jumbled up and Exchange no longer able to send messages.

Apple - please sort this out quickly!

Problem solved by changing servers after deleting old account. This really shouldn't be necessary, but at least it works now.