#2366 new

Unable to get IMAP access to Exchange server working - login failed

Reported by CharlieC | July 20th, 2019 @ 03:00 PM

I am unable to get IMAP access to an Exchange server working. My IT admin tells me that IMAP access is available and gave me settings to use. Indeed the log below seems to confirm that IMAP4 is available. Try as I might, I cannot get it to work.

I get a pop-up window with a message like this:

“A4 NO LOGIN failed.”. Command attempted: “A4 LOGIN ••••••••••”.

I read about the following workaround in the archive and tried that, but it made no difference (even assuming that I did it correctly or that it is applicable)

defaults write com.freron.MailMate MmExchangeAuthPlainWorkaround -bool YES

I am new here, so apologies if the answer to this is obvious.



The log is as follows:

14:32:54 Running action
14:32:54 Sending request (15)
14:32:54 Handling request
14:32:54 Ready to run action (retry count: 0)
14:32:54 Clearing connection to owa.essexcourt.net
14:32:54 Trying to connect to owa.essexcourt.net on port 143 (CFNetwork) with STARTTLS (required)
14:32:54 Resolved hostname (owa.essexcourt.net).
14:32:54 Successful connection.
14:32:54 S: * OK The Microsoft Exchange IMAP4 service is ready.
14:32:54 C: A0 CAPABILITY
14:32:54 S: A0 OK CAPABILITY completed.
14:32:54 C: A1 STARTTLS
14:32:54 S: A1 OK Begin TLS negotiation now.
14:32:54 Initiating secure connection...
14:32:54 Prepare secure connection...
14:32:54 Returned (4)...
14:32:54 Protocol version: kTLSProtocol12
14:32:54 C: A2 CAPABILITY
14:32:54 S: A2 OK CAPABILITY completed.
14:32:54 Retrieving password (keychain or user request)
14:32:54 S: +
14:32:54 C: ••••••••••
14:32:56 S: A3 NO AUTHENTICATE failed.
14:32:56 Error: Server response: “A3 NO AUTHENTICATE failed.”. Command attempted: “••••••••••”.
14:32:56 Retrieving password (keychain or user request)
14:32:56 C: A4 LOGIN ••••••••••
14:32:58 S: A4 NO LOGIN failed.
14:32:58 Error: Server response: “A4 NO LOGIN failed.”. Command attempted: “A4 LOGIN ••••••••••”.
14:32:58 Retrieving password (keychain or user request)
14:33:37 Error: Failed to retrieve password for account.
14:33:37 Error code: 5
14:33:37 Failed action (1000). Reset observed read/write timeouts: 8/8

14:33:37 Handling reply
14:33:37 Terminating non-running connection...
14:35:37 Running action
14:35:37 Sending request (17)
14:35:37 Handling request
14:35:37 Trying to disconnect nicely (30)...
14:35:37 C: R5 LOGOUT
14:35:37 S: * BYE Connection is closed. 13
14:35:37 S: <<< terminated reading >>>
14:35:37 Logout error should not happen (10).
14:35:37 Clearing connection to owa.essexcourt.net
14:35:37 Ready to run action (retry count: 0)
14:35:37 Disconnecting
14:35:37 Clearing connection to owa.essexcourt.net
14:35:37 Completed action (3). Observed read/write timeouts: 8/8

14:35:37 Handling reply

Comments and changes to this ticket

  • benny

    benny July 25th, 2019 @ 02:51 PM

    The output seems to suggest that both LOGIN and AUTH=PLAIN was attempted. Neither was successful. Do you know if the server might have two factor authentication enabled? In that case you would likely need an application specific password.

    Does it work in any other IMAP email clients? (Note that Apple Mail does not use IMAP unless explicitly configured to do so.)

    One possible debug attempt could be to manually connect to the server and see if that works (with LOGIN). I can provide details if needed.

  • CharlieC

    CharlieC July 26th, 2019 @ 02:21 PM


    I checked and two factor authentication is not enabled.

    I have MailMate working with IMAP on iCloud and gmail no problem. I may have misunderstood the question. If you mean have I got the this exchange connection working on IMAP in another email client, then the answer is no. I tried it with Apple Mail (and manually configured it to be IMAP) as well as Thunderbird. No joy with either.

    If you could give me details of how to do a manual connection please I will try that.

  • benny

    benny August 1st, 2019 @ 07:01 AM

    Ok, MailMate might not be the problem (since you cannot make it work in other email clients), but here you go.

    First connect to the server like this (in a Terminal window):

    openssl s_client -connect owa.essexcourt.net:143 -starttls imap -crlf

    (I cannot actually connect myself right now, but I'm also on a very bad internet connection.)

    If it connects then log in like this (replacing with your username and password):

    A LOGIN "username" "password"

    And see what happens...

    You logout like this:

  • CharlieC

    CharlieC August 7th, 2019 @ 08:06 PM

    Thanks Benny.

    I followed the instructions and managed to login no problems on the internal network at work. Does this mean it might be a problem with Mailmate?

    Externally it didn’t work, but the network guys told me they have blocked external access (heaven knows why).

    I will follow up now and try to get Mailmate to work at least on the internal network. I might start by deleting it and reinstalling it.

  • CharlieC

    CharlieC November 30th, 2019 @ 09:33 AM

    Dear Benny
    Just wanted to let you know that I pursuaded my system administrator to turn on IMAP and I now have it working. Yay!
    Thanks for you help in giving me ammunition to get that change.

  • Alex Veer

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