Here are some articles about changing from port 25. You might have to switch to SMTPS.
https://www.ptc.com/en/support/article/CS349913?source=search
https://www.ptc.com/en/support/article/CS407185?source=search
AI Results:
Outbound SMTP connectivity on TCP port 25 is blocked by default for most Azure subscription types, including Pay-as-you-go, for virtual machines (VMs) and this block cannot be removed. Enterprise Dev/Test subscriptions also have port 25 blocked by default, but this block can be removed.
Reasons for this restriction:
- Security and Spam Prevention: This measure is in place to prevent the abuse of Azure resources for sending spam or other malicious email activities.
Alternatives for sending email from Azure:
-
Authenticated SMTP Relay Services:
- Utilize third-party email delivery services like SendGrid, Mailgun, or others that offer authenticated SMTP relay.
- These services typically use alternative ports like 587 (recommended for TLS/STARTTLS) or 465 (for SSL) and require authentication, bypassing the port 25 block.
Contact Azure Support:
If using an Enterprise Agreement or MCA-E subscription and requiring port 25 access, or if facing persistent issues with alternative methods, contact Azure support with the issue type "Technical > Virtual Network > Cannot send email (SMTP/Port 25)".
