I'm running a NestJS backend on Railway and using Nodemailer to send emails via a third-party SMTP server. In production I'm getting this error:

❌ 550 X-Warning: 162.220.232.66 is listed at SPauthBL

It looks like Railway's outbound IP (162.220.232.66) is blacklisted, which causes all SMTP emails to be rejected by Gmail and other providers.

Is there anything I can do to fix this?

• Can Railway rotate or assign a clean outbound IP?

• Or is there a best practice to avoid this issue (e.g. using a relay or proxy for outbound email)?

Would really appreciate any advice or help 🙏

Project: 561808e7-731d-49db-b72b-44c82993152f