SMTP issues random delivery from [Office 365] sender

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    Asked on January 22, 2018 at 02:29 PM

    Hi first of all I am very happy with the e-mail function it is great. I use the auto responder for 2 generated mailadresses and 1 notifcation e-mail.


    I setup SMTP with office 365 and test-mail works great.

    The only problem I have the messages get not all delivered and I don't know why sometimes they get all delivered sometimes 2/3 and sometimes none.

    To test this issue I did the following things:


    * I whitelisted all IP adresses and server according to the faq.

    * I created a transport rule in exchange to ignore any spam filter

    * I checked the ip from the server and marked it as safe which is actually

    * I rechecked my SMTP settings.


    I test all the time with same e-mail adresses and generated e-mail so I am sure the mail adress is correct and I only use one form to test.


    E-mail sent from jotform:
    1516649136jform 1 blur.png

    E-mail in server log. (time is +1 hour for comparison)
    1516649149exchange 1 blur.PNG


    A rule is created making sure it is not marked as Spam.
    1516649164exchange 2 example confidence

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    Answered on January 22, 2018 at 03:42 PM

    Thank you for contacting us.

    I have escalated a ticket to our next level support to see if we can proceed with the further troubleshooting in this case.

    Unfortunately, I cannot provide any ETA for when this will be addressed, but we will get back to you once we have any updates.

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    Answered on January 23, 2018 at 02:01 AM


    We checked our email logs and found that you have an authentication problem. 

    [22/Jan/2018:08:00:01 -0500] SMTPProxy :: Failed email to ( SMTP Error: Could not authenticate. )

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    Answered on January 26, 2018 at 04:12 AM

    Thanks for the quick and reponse in detail. However I have no clue how to solve this. The credentials are correct I am sure. On the Internet I read this is happening to a lot of people who use office 365. Maybe a more detailed log can help.

    Thanks in advance.

  • Profile Image
    Answered on January 26, 2018 at 06:48 AM

    Can you please contact Office 365 support regarding the issue? Let us know if you have any additional question.