SharePoint 2016 on premise mailing issue "Relay access denied"

Question

This is regarding the mailing issue we are facing in our SharePoint 2016 on-premise environment. My organization does not allow anonymous authentication for external SMTP servers. We are no longer using a virtual SMTP server and are only allowed to use an external server. However, there is no way to configure credentials for outgoing emails from Central Admin. Whenever a Nintex workflow triggers a notification email, we receive the error: "Relay access denied." Is there any way to use Secure Store Service to pass credentials for the external SMTP server whenever Nintex workflows trigger emails?

Can we use Microsoft Graph API to connect an external SMTP server with SharePoint 2016 on-premise? Which method is possible and the easiest?

Answer 1

Hello Lazy Bee,

Thank you for reaching out to Microsoft!!

Regarding the query mentioned, is it possible to connect to an external SMTP server with SharePoint 2016 on-premises using Microsoft Graph API, Unfortunately Microsoft Graph API does not support SharePoint on-premises functionalities. Hence it is not possible at this moment to connect to an external SMTP server with SharePoint 2016. Apologies for the inconvenience caused.

Please find the below links for reference:

configure-the-secure-store-service

secure-store-service-planning

Also, please find the related post here:

https://learn.microsoft.com/en-us/answers/questions/1103499/does-microsoft-graph-api-support-sharepoint-on-pre

Hope this helps.

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