u/Marcos-Perez-

Good morning,

I'm having some troubles setting up Email Marketing with a custom domain.

Context:

• Odoo version: 19.0+e Enterprise
• Email provider: Office365

When I was sending a marketing campaign, everything seemed to work correctly at first. However, I noticed that some emails are being bounced and it's not showing bounced in Odoo. When the bounce alias is configured.

After investigating, I found out that the 'Return-Path' header is being changed to the same address as the sender's email.

It appears that Office365 has security measures for anti‑spam, anti‑spoofing, etc. that forcibly override this header.

Therefore, I would like to ask:

• Has anyone else experienced a similar issue with Office365?
• What workaround did you implement?

Thank you so much in advance for your help.