Hi @noise ,
What you’re seeing is actually expected behavior when using the Gmail API.
When you authenticate Post SMTP with Gmail API using bert@gmail.com, Google’s API checks the From address against the list of “Send mail as” aliases configured for that Gmail account. If info@domain.com isn’t registered as an authorized alias, Google overrides the sender back to bert@gmail.com, even though Post SMTP is sending the correct headers. This is a restriction enforced by Google, not by Post SMTP.
To fix this:
- Go to Gmail > Settings > See all settings > Accounts.
- Under “Send mail as”, click Add another email address.
- Enter info@domain.com.
- Gmail will send a verification email to that address.
- Verify it so it becomes an authorized Send mail as alias.
- In Post SMTP > Settings > Message tab, set the From Email to info@domain.com and save your changes.
Once the alias is verified, Google will allow Post SMTP to send using that address.
Alternatively, if info@domain.com is also your site’s primary email address, you can grant permission with it to send.
Let us know if that resolves the issue.