Here's my project ID: 053e6cf6-fc14-475c-be33-f456f31bc7e2

SMTP outbound traffic is only available on Pro and Enterprise plans.

That is a recent change to prevent spam and abuse.

https://docs.railway.com/reference/outbound-networking#email-delivery

I see, thanks for your help

You can still send emails by using transactional email services with HTTPS APIs (like Resend)

My use case isn't to send emails per se, I mainly just want to open a TCP connection to check that the mail server is running

Is there a way I can open the connection and just not send any data? That would be fine for my use case

Unfortunately there isn't any client-side hack you can do to complete that TCP handshake to the SMTP port

Alright, no worries!

!s