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SMTP server doesn't Support STARTTLS

Anonymous
2017-04-27T14:17:02+00:00

Hi,

I'm Getting this error for SMTP server "SMTP server doesn't Support STARTTLS"/"Unable to connect to server. Check server name and port." in two different email clients.

I'm trying to configure a email client with a office365 email. The OS is Server 2012 Standard. All the ports are open in firewall.

POP3 is configured and working with port 995 (SSL enabled)

For SMTP

Port: 587

TLS enabled

Microsoft 365 and Office | Subscription, account, billing | For home | Windows

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  1. Anonymous
    2017-04-27T20:09:20+00:00

    Hi Dibyendu,

    Regarding “I'm trying to configure an email client with a office365 email”, it seems you are using SMTP client submission to send emails with Office 365 account. If that is your case, here are the requirements for SMTP client submission:

    Authentication: you need to configure a user name and password to send email on the device.

    Mailbox: you need a licensed office 365 mailbox to send email from.

    **Transport layer security (tls):**your device needs to use tls version 1.0 and above.

    Port: port 587 (recommended) or port 25 is required and needs to be unblocked on your network. Some network firewalls or isps block ports—especially port 25.

    For more information, please refer to Option 1 (SMTP client submission) section of this articleand check if all settings are correct.

    If all settings are correct and you can’t send out email using Office 365 account either, I recommend you test if the Office 365 server is working properly for this account for SMTP client submission. To test it, we can use Outlook client. Here are the detailed steps:

    1. Create a new outlook profile according to the following link:

    https://support.office.com/en-us/article/create-an-outlook-profile-f544c1ba-3352-4b3b-be0b-8d42a540459d?ui=en-us&rs=en-us&ad=us 2. Click manual setup or additional server types. 3. Choose POP or IMAP button. 4. Input the information like what the screenshot shows below:

    5. Click more settings and set as the following screenshot shows:

    6. Click ok to save.

    After the configuration, if you can successfully send and receive messages, it means the office 365 server is fine when using SMTP client submission. And the issue may be related to the server. Given the situation, we recommend you contact the IT administrator of your organization for further investigation.

    If you can’t send and receive emails, please let us know so that we can further assist you.

    Thanks,

    Gary

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  1. Anonymous
    2017-05-04T14:04:30+00:00

    Hi Dibyendu,

    Thanks for your response. Regarding you can’t send emails after you configure the Office 365 account in the Outlook client via the method I mentioned above, I’d like to confirm whether you have checked “Use same settings as my incoming mail server” under “My outgoing server (SMTP) requires authentication”. If not, please check it and test you can send emails out.

    If you can send emails normally, it indicate the Office 365 server works fine when using SMTP client submission. Given the situation, it is recommended you contact your IT administrators of your organization for further investigation.

    Thanks,

    Gary

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  2. Anonymous
    2017-05-04T07:36:58+00:00

    Hi Gary,

    Thanks for the step-by-step guide.

    I have tried the mentioned settings but its not working. But i got a work around. I have setup the mail using Exchange settings and it worked.

    There are different variable that needs to considered, like it's a server which is behind a firewall which i have no control of. Moreover i was trying to configure it in a separate application not an email client so some options were limited. I tried with a gmail account with the SSL enabled using 465 port which work, but was the same error while using TLS at 587. I still don't understand what went wrong.

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  3. Anonymous
    2017-04-30T08:21:25+00:00

    Hi Dibyendu,

    Have you referred to my reply? Any updates?

    Thanks,

    Gary

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