El Capitan Mail send error

Dear Larry,

Have you had a change to rebuild the mailbox, this is what I did a couple of times and than I changed the settings for the account. You can rebuild the settings in the mailbox menu. After rebuilding shut down mail and restart mail again, than adjust the authentication settings. It worked for me, but I don't have a iCloud mail account. Hope you can sort it out. BTW I've had a chat with the Apple support yesterday, and they don't know about a general email issue.......not yet I suppose.

J Til2D - Thanks for your note. Your comment that Apple Support doesn't know the there's a general email problem yet is because they must not want to know. I've been to Genius Bar, also spoke with Apple Support by phone, specifically asked that they make others aware that this is a very common problem now according to the discussion boards, AND also according to one of the developers who posts here who said that this problem was first noted back during the beta tests and the developers all reported it, plus I've sent in a detailed Mail Feedback report. Sadly, I'll assume that the fact that they are still saying the t they are unaware of an El Capitan email sending problem means that we shouldn't expect a fix in 10.11.1 when it comes out. By the way, I hope that those up here who are excited the they've solved this don't have the problem recur, but in my case, I've spent lots of time over the last week or so just changing the smtp settings in Mail for accounts, sometimes it doesn't do anything, sometimes it works right away but eventually reverts, sometimes it works for 10 seconds and then reverts to not working. ???

Thanks Larry for your kind answer, hope for you that Apple will sort it out, have you rebuild your mailbox yet? That could be helpful.

Hi Dave. I'm curious if you know any more about this, since suddenly, sending started working fine, even if I closed my Mail/Preferences, and has been that way for a few days now. You seemed to have the best understanding of what the problem probably was, so I expected that it would only be fixed in 10.11.1 where they might have fixed the code to capture the SMTP parameters and save them. But now that it's working (hopefully will stay this way) without 10.11.1, do you happen to have any new info as to how they fixed it? Thanks!!

I had this problem, what solved it for me was disabling SSL.

I just looked and my SSL is enabled. To be frank, I don't intend to change anything at this point, since it is working. But there seems to be no one correct answer with this. It appears that each of us who had a problem just kept randomly trying things until eventually our outgoing mail just worked and continued to work. I continue to hope that Apple includes something in 10.11.1 that fixes this permanently for everyone, but until that happens, I'm happy for any of you whose Sending problem went away, no matter what they did, and I'm not going to change a thing since mine is working. I probably shouldn't even look at Mail's Preferences again, since I fear that even if I don't change anything, the system will see that I opened Mail's Preferences and change something by itself.

There seems to be no specific answer to this. What fixed it on my MBP was no help on the new MacBook. When I rang Apple they suggested several things, all of which I'd tried without success. They more or less admitted they didn't know the answer.

Very helpful.

Thank you so much. I really appreciated this helpful tip.

In case anyone here still has the problem and hasn't installed the 10.11.1 update that came out a few days ago, that seems to have fixed the problem for most people. Apple's description of the update said that it fixes an issue where outgoing server information may be missing from Mail, so I guessed that meant that they found whatever messed that up when installing El Capitan and that they undid that. Does anyone who posted to this thread still have the problem?

I uploaded to 10.11.1 and I still get the SMTP server problem. No hope for me, then?

There's always hope. 10.11.2 will be out eventually. As I said, my mail began to send before 10.11.1, after a long period of not working. You should also talk with your ISP and get it involved, or you can always take your system into a Genius Bar at an Apple store and leave it with them to try to fix. That had been their last suggestion to me when mine started working again. Or try another email program, such as Outlook, since someone posted here that that solved his problem.

i have deleted all mailaccounts and created new accounts with the same settungs as the old. since these action all problems were solved.

I have the SMTP server going "offline" problem also - on 3 of my 4 smtp accounts - actually, 3 email accounts, one with two totally separate smtp services and two of the accounts use the same Microsoft smtp.office365.com service. What happens is that all smtp works for awhile then 3 of the 4 quit with offline ssl may not be supported errors in connection doctor. The one that stays going is an old non-microsoft server kept going when the university I work for switched to office365 hosting for email. Two of the three that quit are the office365.com. One is at fatcow.com.

Looking at the Mail smtp logs. They show good connection when streams security level is none. Then fail when the security level is TLSv1. If I reset my internet gateway router, which is an old Linksys WRT54G, the smtp services all come back up. The ones that go out usually do so after a few hours of working. I do know the Linksys has an expired certificate, but I have set it to always trust via keychain manager. The cert could be a problem, but I do not think the router itself is.

I have deleted and rebuilt the accounts in Mail preferences and accounts more than once. I now have all the "automatically detect settings" turned off for all accounts as a last ditch effort. Luckily, the one old server/service stays going and will accept sends from enough of my email addresses that I am not dead in the water.

I did not notice this until I had done the 11.1 update, but did not run for long after my original El Capitan upgrade. I would guess the problem is the ssl negotiating process is breaking with newer smtp services. Hopefully, Apple will fix this quickly.

It can't hurt to send Apple that info on their Mail Feedback form at http://www.apple.com/feedback/mail.html

Since many of us stopped calling Apple Support or visiting the Apple Genius Bar at an Apple Store to tell them about this since our problem suddenly went away, perhaps you want to do one of those things just to get the word Mail back on their priority list.

(And if all else fails, many who switched to Outlook reported that solving their problem.)

I had this problem until this morning (mail wouldn't send since upgrading to El Capitain). I have fixed the problem in as much as I can now send emails through mail again, but had to log out my apple id on the computer to do it. The problem seemed to be that I was sending mail from an email address that was also my apple id. To clarify, prior to upgrading I had three email addresses enabled on mail, no problems with any. One of those (my main address) was also my apple id. After upgrading I could not send anything from that account (and I tried all the fixes suggested here). This morning I removed the account from mail and internet accounts, unchecking every box available, logged out my apple id on the computer (and logged in as my husband - we share devices), and then added the email account back to the mail. Now I can send mail again. I don't know why this is a problem with El Capitain, but if the email address you are having trouble with is also your apple id, this could be it...