What SMTP relay service are you using?
SendGrid is the SMTP relay service we recommend using with Azure App service.
Common SendGrid use cases include:
- Automatically sending receipts or purchase confirmations to customers.
- Administering distribution lists for sending customers monthly fliers and promotions.
- Collecting real-time metrics for things like blocked email and customer engagement.
- Forwarding customer inquiries.
- Processing incoming emails.
Please follow this tutorial to set up SendGrid for your apps on Web apps & DevOps
Hope that helps.
-Grace