Yes. When I put the English language, the activation email is sent perfectly.

Do I also successfully sent the activation email with the Spanish language?

Thanks

Thanks for the help:

1 .- I did not install any extensions.

2 .- Where I see the "errors appeared in php error log? No error appears when I do the registration and the PunBB warns correctly that sent the email to new user

3 .- Yes I am using a general template "oxygen" in Spanish. But what is an email template?

4 .- I installed punbb UTF8, because my base Mysql is uft8_spanish_ci.

Please, I continue to need your help. Thanks

The option "Require verification of all new registrations by e-mail" (even with smtp options),  send of the new user an empty email and classified as spam.