Hi,
The answer was (partially) in Password reminder email not provide the mailbox - #9 by chahor . The reason why the email was not being sent was the sender email, which is configured at the Technical Support of the conference. Apparently the mail server was blocking the sender. I’m not sure, but the safer is to use the email set at the stmp configuration.
This is a little bit weird, because this configuration is not related to a conference, but to the whole system. I hope this is already solved in OCS 3, and I hope someday I’ll have time to migrate 
best,
alan