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Mail Error on Auth: 535 5.7.139 Authentication unsuccessful

Anonymous
2024-02-20T09:18:07+00:00

Hello,

We are using Office365 business basic. We are using one of our licensed account for SMTP email to send main to our users (outsiders). Our smtp client is written on GO lang. The service was working fine, but recently we found that the service can't send mail for some authentication issue. But in our local pc everything is working fine, even the same code/ program is working fine in our local pc. But when we try to send from our servers it throws error. We tried with many clients locally, everything is working fine. May be our servers added on blacklist or something else.

Outlook | Web | Outlook on the web for business | Email

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  1. Anonymous
    2024-10-16T18:43:22+00:00

    In German I found evidence that the service was discontinued on September 16th. If you add a few days until an update is made, that's roughly the case.

    Moderne Authentifizierungsmethoden sind jetzt erforderlich, um die Synchronisierung von Outlook-E-Mails in Nicht-Microsoft-E-Mail-Apps fortzusetzen - Microsoft-Support

    2 people found this answer helpful.
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  2. Anonymous
    2024-10-08T06:01:50+00:00

    Dears,

    I get the same error "535 5.7.139 Authentication unsuccessful, basic authentication is disabled"

    I have a personal email on @outlook.com

    1 person found this answer helpful.
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  3. Anonymous
    2024-02-20T16:57:07+00:00

    Hello there

    Thanks for your response. I have tried for both legacy and standard version. Both cases are working fine locally, but throwing error in my servers. I am not using MFA so those are not applicable here I guess. I checked our domains blacklist status, but they are not.

    1 person found this answer helpful.
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  4. Anonymous
    2024-02-20T12:41:50+00:00

    Thanks for the response, I know there are a lot of security break changes there. But my question is if it is about protocol then it should response same for all request right? When I send mail using the same code script from my machine, even another multiple machine it successfully delivered the mail to the target user. But when I run the same code on my servers it throws error.

    1 person found this answer helpful.
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  5. Anonymous
    2024-02-20T09:37:17+00:00

    package main

    import (
"net/mail"

"github.com/go-gomail/gomail"
"github.com/qor/mailer"
"github.com/qor/mailer/gomailer"
)

func main() {
dailer := gomail.NewDialer("smtp.office365.com", 587, "******@mydomain.com", "mypassword")
sender, err := dailer.Dial()
if err != nil {
	panic(err)
}

// Initialize Mailer
Mailer := mailer.New(&mailer.Config{
	Sender: gomailer.New(&gomailer.Config{Sender: sender}),
})

Mailer.Send(mailer.Email{
	TO:          []mail.Address{{Address: "******@gmail.com", Name: "Rafiul Islam"}},
	From:        &mail.Address{Address: "******@mydomain.com"},
	Subject:     "subject",
	Text:        "text email",
	HTML:        "html email <img src='cid:logo.png'/>",
	Attachments: make([]mailer.Attachment, 0),
})
}

    This code block is working fine on my local machine, but when I try to execute from my server, it throws error.

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