• Email from Mail on my iPhone to Gmail address failed

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    I got a failure reply to an email I sent from Mail on my iPhone to a Gmail address in my contacts.  The same mail sent fine on my computer from Outlook.  My ISP provider is IONOS which hosts my private domain.  It looks like a security issue of some kind from Google.  I’ll post the failure reply below and ask if anyone can decode it to help me resolve the issue:


    This message was created automatically by mail delivery software.

    A message that you sent could not be delivered to one or more of its recipients. This is a permanent error.

    The following address failed:

    SMTP error from remote server for TEXT command, host: gmail-smtp-in.l.google.com ( reason: 550-5.7.26 This mail is unauthenticated, which poses a security risk to the
    550-5.7.26 sender and Gmail users, and has been blocked. The sender must
    550-5.7.26 authenticate with at least one of SPF or DKIM. For this message ,
    550-5.7.26 DKIM checks did not pass and SPF check for [******.com] did not pass
    550-5.7.26 with ip: []. The sender should visit
    550-5.7.26 https://support.google.com/mail/answer/81126#authentication fo r 550 5.7.26 instructions on setting up authentication. 84-20020a25185700000
    0b00b61edf21a8fsi29710677yby.127 – gsmtp

    — The header of the original message is following. —

    Received: from smtpclient.apple ([]) by mrelay.perfora.net
    (mreueus003 []) with ESMTPSA (Nemesis) id 0MS4Ue-1ps3Qv0vMo-00TGuw for <s**********@gmail.com>; Mon, 27 Mar 2023 03:59:55 +0200
    Content-Type: multipart/alternative; boundary=Apple-Mail-4CA8FB79-EFCA-45D8-8F6C-5C5613F2A8B1
    Content-Transfer-Encoding: 7bit
    From: Ronnpj <r******@******.com>
    Mime-Version: 1.0 (1.0)
    Subject: Re: March 25 Lumberjack
    Date: Sun, 26 Mar 2023 19:59:44 -0600
    Message-Id: <3384AA9E-1D11-4181-A0ED-81161C448180@*******.com>
    References: <CAKyN-DSNJvrT2iEfWcYX27LECOpGo3tid6MKEPqjjKVWePVirQ@mail.gmail.com>
    In-Reply-To: <CAKyN-DSNJvrT2iEfWcYX27LECOpGo3tid6MKEPqjjKVWePVirQ@mail.gmail.com>
    To: S******* <s*********@gmail.com>
    X-Mailer: iPhone Mail (20D67)
    X-Provags-ID: V03:K1:c6i1k7c88cWe9ykq52pDu/VDcd5wjwEj4g///7OVBMpe8xDjCH0
    X-Spam-Flag: NO
    UI-OutboundReport: notjunk:1;M01:P0:vQ2O2WlWW6E=;ULzFJnx1OqVtHTOVD9RJBUTg1uZ


    Moderator Note: Edit to remove personal information. Posting personal information such as email addresses poses a security risk. Please do not post personal information.

    Retired Rocket Scientist

    Viewing 4 reply threads
    • #2547512

      550-5.7.26 DKIM checks did not pass and SPF check for [ronnpj.com] did not pass

      Have your host check your spf and/or dkim settings on your domain

      Never Say Never

    • #2547666

      OK, here’s the response from my domain host:

      “Thanks for contacting IONOS,i have added  an SPF record to your domain, you will have to wait for 24 hours for it to get propagated .”

      So that makes sense based on your recommendation.

      Just a couple of questions if you don’t mind.

      What is an SPF record?

      If it’s related to my domain which connects to my own email address why is the problem I’m seeing only connected to a Gmail contact?

      Is there something unique that Google requires for their security purposes?

      Trying to get a little smarter here…


      Retired Rocket Scientist

      • #2547670

        This will probably explain better than I can.

        We set DKIM and SPF records on all domains we host as it drastically improves deliverability. On sites sending newsletters and stuff we go through the arduous process of DMARC. That’s a MUCH larger pain. In my experience gmail seems the most picky and just plain stupid sometimes.

        Tell them while they are at it to setup the DKIM too!

        Never Say Never

        • #2547943

          Great reference!  I think I’m getting it…

          About DKIM, here’s my host’s response:

          Thank you for contacting IONOS.Unfortunately, IONOS doesn’t provide support for the implementation of DKIM records.

          Yet you can set a DMARC record,  for this, please click on the following link for information on how to implement this on your domain DNS settings:



          I’ll try to confirm I can email to Gmail with just the SPF now set.

          Guess I’m not paying enough for my host to set up the DKIM…

          Retired Rocket Scientist

    • #2547743

      Tell them while they are at it to setup the DKIM too!

      I had exact same problem as you @DrRon (different hosting provider though), primarily with google rejecting emails. Solution is as stated by others above (spf + dkim). I fully agree with @cyberSAR that dkim should be used as well as spf.


      • #2547945


        Did your host set up the DKIM for your account?

        Retired Rocket Scientist

        • #2547955

          Did your host set up the DKIM for your account?

          They did originally but I looked into how it worked and how to get log in to the ‘CPanel’ (which I assume stands for Control Panel) and do it myself.

          I know you initially said you’re a bit out of your depth but I was as well when I started looking into why my emails to gmail recipients were bouncing. Adding SPF/DKIM sorted it out and I’m now experimenting with DMARC but I’m not sure it will be necessary in the long run.

          I had a quick look at IONOS but couldn’t see anything obvious. Maybe you could try loging into https://login.ionos.com/ and see if there is anything there calling itself a CPanel. On my hosting provider I then select Zone Editor > Manage Domain and a list of all the domain records came up. This might help ionos cpanel login | how to access cpanel in IONOS 1&1 step by step guide.

          Do a web search for how SPF/DKIM/DMARC work. The descriptions are generally ok but often don’t cover all the fields in each protocol. The definitive references are a bit technical but they are here Sender Policy Framework (SPF) (RFC 7208), DomainKeys Identified Mail (DKIM) (RFC 6376– see Section 3.6 for all fields), and Domain-based Message Authentication, Reporting, and Conformance (DMARC) (RFC 7489 – see Section 6.3 for all fields)

    • #2547957

      If it is cPanel it’s not too hard to do yourself (which would also be a knock against your host)


      Never Say Never

      • #2547961

        I also found these IONOS specifc guides: https://www.ionos.com/digitalguide/e-mail/e-mail-security/dkim-domainkeys/ and Using an SPF Record to Prevent Spam.

        My experience with the hosting help desks has been pretty discouraging. When they first set up my SPF they added two SPF records – but you’re only allowed to have one! That’s when I started looking into it and getting my head around it. It didn’t turn out to be that hard and worth it as you are then in control of your domain. Other than the DKIM private key, the rest of the information is published in the DNS sytsem so if you want to post the settings you want to try here someone will be able to tell you if they work or not.

        You can see what your current settings are using sites like this https://mxtoolbox.com/SuperTool.aspx, putting in your domain and then selecting the type of lookup you want on the right. For example, if you plug google.com in as the domain and do a SPF lookup you get “v=spf1 include:_spf.google.com ~all” and similarly for DMARC you get “v=DMARC1; p=reject; rua=mailto:mailauth-reports@google.com”. DKIM is a bit harder as you need to know the selector (you can do a web search on how to find your selector), for google this is dkim:google.com:20210112 and the results are “v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAq8JxVBMLHZRj1WvIMSHApRY3DraE/EiFiR6IMAlDq9GAnrVy0tDQyBND1G8+1fy5RwssQ9DgfNe7rImwxabWfWxJ1LSmo/DzEdOHOJNQiP/nw7MdmGu+R9hEvBeGRQAmn1jkO46KIw/p2lGvmPSe3+AVD+XyaXZ4vJGTZKFUCnoctAVUyHjSDT7KnEsaiND2rVsDvyisJUAH+EyRfmHSBwfJVHAdJ9oD8cn9NjIun/EHLSIwhCxXmLJlaJeNAFtcGeD2aRGbHaS7M6aTFP+qk4f2ucRx31cyCxbu50CDVfU+d4JkIDNBFDiV+MIpaDFXIf11bGoS08oBBQiyPXgX0wIDAQAB”.

    • #2548084

      Wow… feel like I’m back in Graduate School!

      You guys are really impressive or I’m getting really old – or both!

      Changing any DNS setting on my domains scares the heck out of me.

      Currently just the SPF change seems to have resolved my Gmail delivery problem.  So maybe I’ll take some time to study your references and browse my host site to see if I can find a way to add the DKIM setting.

      Looking at DMARC and the FTP stuff just boggles my mind.

      So for now maybe I’ll mark this one resolved and wait to see if I can get my school juices flowing again.

      I do appreciate the help.

      Retired Rocket Scientist

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