Error sending mail in V12

Hello,

i use two instances of ProjeQtOr for testing two different purpose (one in V11.4.2, one in V12.3.0).
The two instances have same mailing configiration (same smtp server, same accounts,...). Global parameters page are strict copy from one to the other.

When i test sending mail fraom V11.4.2, i get :
émetteur de l'email : This email address is being protected from spambots. You need JavaScript enabled to view it.
Email envoyé à This email address is being protected from spambots. You need JavaScript enabled to view it.
and the mail is received.

From V 12.3.0, i only get 
émetteur de l'email : This email address is being protected from spambots. You need JavaScript enabled to view it.
and no mail is received.

I try to send mail directly via telnet on the smtp server and it works fine (same server than for V11.4.2).

No error in log, even in debug mode (only trace ====/tools/sendMailTest.php

Any help ?

Regards

Find the bug : option Do not receive your own mail is active even in test mode for mail configuration.
So, you don't receive test mail if you are using your proper account. This is not intuitive...