Office365 SMTP Timeout error

Question

Hi!

When sending an email through office365 SMTP, we get this error: "read tcp 111.11.11.111:11111-u111e11.11.111.111:111: 1/0 timeout" (numbers are censored).

What can be the problem?

Thanks.

Answer 1

Hello BlinkOps Lab Account,

Thank you for reaching out to us in the Microsoft community.

I understand you're experiencing a timeout error when sending an email through Office365 SMTP. This issue could be due to network connectivity problems, server overload, or incorrect SMTP settings.

To address this, please have your Organization's IT administrator verify that the affected domain is correctly configured with the domain provider. Below are some examples of the necessary configurations to check, which may need to be published on the DNS service provider's site if required.

For sending emails from multifunctional device, an SPF record is required. Microsoft recommends the following SPF record format:

v=spf1 ip4:

For example:

v=spf1 ip4:xxx.xxx.xx.xxx ip4:xxx.xxx.xx.xxx include:spf.protection.outlook.com ~all | Device or application setting | Value | | --- | --- | | Server/smart host | Your MX endpoint, for example, yourdomain- com.mail.protection.outlook.com | | Port | Port 25 | | TLS/StartTLS | Must be enabled and only TLS 1.2 is supported | | Email address | This can be any email address. |

Also send email to external recipients update the connector with new IP address. | Connector setting | Value | | --- | --- | | From | Your organization's email server | | To | Microsoft 365 or Office 365 | | Domain restrictions: IP address/range | Your on-premises IP address or address range that the device or application will use to connect to Microsoft 365 or Office 365 |

For more information, Please go through How to set up a multifunction device or application to send emails using Microsoft 365 or Office 365 | Microsoft Learn

To enhance the security of your email environment, we kindly request the publication of DKIM and DMARC records for all custom domains. Implementing these measures will help recipient servers verify that emails originate from authenticated senders/sources.

To create DKIM keys, navigate to Microsoft 365 admin center > Security > Policies & rules > Threat policies > Email authentication settings > DKIM > select the domain you wish to configure. A pop-up window will appear, and you can Create DKIM keys. Copy and share it with concern DNS provider.

Record Type: CNAME (*******.com)

Host: selector1._domainkey.*******

Points to address or value: selector1-*******_domainkey.*********.onmicrosoft.com

TTL: 3600

Record Type: CNAME (*******.com)

Host: selector2._domainkey.*******

Points to address or value: selector2-*******_domainkey.*********.onmicrosoft.com

TTL: 3600

After waiting for propagation, which might take up to 24 hours, DKIM can be enabled from the Microsoft 365 Security portal. To enable DKIM, navigate to Microsoft 365 admin center > Security > Policies & rules > Threat policies > Email authentication settings > DKIM > select the domain you wish to configure. A pop-up window will appear, and you can enable DKIM from there.

For more information please go through How to use DKIM for email in your custom domain - Microsoft Defender for Office 365 | Microsoft Learn

Concerning DMARC, I kindly request you to publish the DMARC TXT records to your DNS service provider's site, following the example below:

Example: _dmarc.contoso.com 3600 IN  TXT  "v=DMARC1; p=quarantine" (Policy set to quarantine )

For details information: Use DMARC to validate email, setup steps - Microsoft Defender for Office 365 | Microsoft Learn

If the issue still persists after checking/performing these steps, your current scenario should be diagnosed by Microsoft's frontline support team by collecting some more advanced logs information via remote session. Frontline technical support engineer can also involve specific support team for further analysis some particular situation if it is required. 

Since we forum moderators have limited permissions and access resources, due to this reason and for data privacy of users, we are unable to collect certain kind of logs information in the public forum. 

After diagnosing the scenario, our technical support team can provide possible information from their end. 

If there are any known issues, this information can be provided by the technical support engineer from their backend resources. 

For the above provided standard process information, in your organization, Office 365 global admin person may need to contact Office 365 support team on backend via an open service request so they can diagnose this specific scenario through some more technical resources, 

For this standard process, here's the official document for the global admin reference: Get support - Microsoft 365 admin | Microsoft Learn (Online Option). 

Note: If you are an end-user person, you may need to contact the Office 365 global admin person in your business organization for connecting with technical support engineer for further process. 

Important note: If any organization's Office 365 Business/Business/Education subscription is from a syndicated partner or reseller, and if the global admin can't open the service request on their end, they may need to contact the reseller's support provider so they can help the global admin to open the service request on their end. after the Office 365 support team will involve in the created service request. 

Your cooperation precious time is highly appreciated. 

Sincerely

Feroz Mahmud | Microsoft Community Moderator