Hi,

Edited to match the issue posted on github.com to avoid confusion.

The summary:

Odoo acts as the relay service for unknown email address (outside the companydomain.com) causing the email not only marked as SPAM but deleted outright.

The expected behaviour is Odoo should stop acts as the relay service for unknown email address, instead Odoo will use the Outgoing Mail Server record with higher priority number to send the email.

Impacted versions: 13.0

Steps to reproduce:

1. Enable the G Suite SMTP relay service.

Allowed senders: Any addresses (not recommended)

Only accept mail from the specified IP addresses: Yes

Allowed IP addresses: Odoo server ip address

Require SMTP Authentication: No

Require TLS encryption: Yes

2. Configure the Outgoing Mail Server

a. G Suite SMTP relay service
Priority 1

Connection Information
SMTP Server | smtp-relay.gmail.com
SMTP Port | 587

Security and Authentication
Connection Security | TLS (STARTTLS)

b. G Suite SMTP
Priority 5

Connection Information
SMTP Server | smtp.gmail.com
SMTP Port | 465

Security and Authentication
Connection Security | SSL/TLS
Username: catchall@companydomain.com
Password: xxxxx

Current behavior:

1. someone@rocketmail.com send an email to hello@companydomain.com

2. Odoo create new record / Lead.

3. companyrep@companydomain.com send a reply.

4. someone@rocketmail.com receive the email and reply it.

5. Odoo fetch the email and **act as the relay service** for @rocketmail.com **note: This is should not happen**

6. companyrep@companydomain.com **did not get notified since he did not receive the email.**

Note: Odoo only use the record with lower priority number (continue to act as the relay service even to unknown email), the higher priority number is ignored although the email is not @companydomain.com

**Expected behavior:**

6. **Odoo did not acts as the relay service for unknown email, instead use the Outgoing Mail Server with higher priority number.**

Note: I set 2 records for Outgoing Mail Server (one with smtp-relay.gmail.com and one with smtp.gmail.com)

a. G Suite SMTP relay service

Priority 1

**Connection Information**

SMTP Server | smtp-relay.gmail.com

SMTP Port | 587

**Security and Authentication**

Connection Security | TLS (STARTTLS) 

b. G Suite SMTP

Priority 5

**Connection Information**

SMTP Server | smtp.gmail.com

SMTP Port | 465

**Security and Authentication**

Connection Security | SSL/TLS

Username: catchall@companydomain.com

Password: xxxxx