Hi,

In Odoo 17 CE, this usually means your SMTP connection works (since the test passes), but the email is being blocked when actually sending invitations. Common causes are:

1. Check the Sender Email

    • Go to Settings → Technical → Email → Outgoing Mail Servers.

    • Ensure the Username / From email matches what your SMTP provider allows.

    • Many providers (e.g., Gmail, Outlook, Microsoft 365) block sending emails if the From address is different from the authenticated user.

Example: If your SMTP login is info@mycompany.com, then the sender must also be info@mycompany.com.

2. Check the “From” Catchall Email

    • Go to Settings → General Settings → Email.

    • Under Alias Domain / Catchall Email, make sure the default outgoing email is a valid, authorized mailbox.

3. Review the Failed Email in the Queue

    • Navigate to Settings → Technical → Emails.

    • Open the failed invitation email.

    • Look at the error message in the “Failure Reason” field — this usually reveals if it’s an SMTP authentication error, relay issue, or invalid sender.

Hope it helps.

had the same - indeed need to check for error in Technical tab, which will become visible after you enable Developer mode 

there you will find messages queue and from there bounce error etc