18 days ago
We have a .NET application deployed on Railway trying to connect to an external SMTP server.
Target:
Host: mail.plain.pt
Port: 587
TLS: STARTTLS
The application times out while opening the TCP connection:
Connecting to SMTP server mail.plain.pt:587 using StartTls with timeout 15s
Failed to send email after 15000ms
ErrorType=System.TimeoutException
Stack: MailKit.Net.SocketUtils.ConnectAsync / SmtpClient.ConnectAsync
The SMTP provider confirms:
- ports 465 and 587 are open;
- SMTP service is active;
- no connection attempts reached their server at the tested timestamps.
Could you help us?
1 Replies
18 days ago
Your workspace is on the Hobby plan, and outbound SMTP is only available on the Pro plan and above. This is why the TCP connection to mail.plain.pt:587 times out and no connection attempts reach the remote server. You can either upgrade to the Pro plan (and redeploy your service afterward) or switch to a transactional email service that uses HTTPS APIs, such as Resend, SendGrid, or Postmark. More details are in our outbound networking docs.
Status changed to Awaiting User Response Railway • 18 days ago
Status changed to Solved lynxdabliu • 18 days ago