Hello Everyone,

I'm looking to implement an SMTP Proxy for OUTBOUND mail with NGINX. The backend stream servers are remote.

SMTP clients ---------> NGINX SMTP Proxy (2501) -----------------> Remote SMTP server (25) without Authentication.

The NGINX SMTP Proxy works fine with regular SMTP clair text traffic on port 25, but it's not working with remote SMTP with STARTTLS on port 587.

I'm getting this error
[error] 7424#7424: *6 upstream sent invalid response: "530 #5.7.0 Must issue a STARTTLS command first" while reading response from upstream, client: .xxx.xxx.xxx.xxx using starttls, server: 0.0.0.0:2501

Can you please hlep me to resolve this ?

Thank you in advance