How to fix 'Remote server returned '550 5.7.708 Service unavailable' while sending emails through postman.

Question

I am able to send mail through Graph API but it is not received by the recipient. I have added O365 licenses and given all the permissions to the application which was created in the Azure portal. An access token is generated differently for the @outlook.com domain and onmicrosoft.com. Please help!

Answer 1

Hi @ShivaKarthik Rao ,

Welcome to our forum!

Would you please provide more information about the error 'Remote server returned '550 5.7.708 Service unavailable'? Such as a screenshot. (In order to avoid privacy, please remember to hide your personal information.)

Based on my research on the error "50 5.7.708", this error can happen when you are trying out a Microsoft 365 trial tenant. More information: 5.7.708 Access denied, traffic not accepted from this IP.

In addition, i found a similar thread as yours, it's suggested that you could try the suggestion as Oliver Wu MSFT mentioned:

Hope to help you!

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.