Can you doublecheck that user under which you are trying to add members (if it is not an admin) can browse (do it in Share) to Repository->Data Dictionary->Email->invite? Do you also see Spanish (invite-email_es.html.ftl) version of the template there? (Just guessing that your Share interface is in Spanish.)
Change the name of invite-email_pt_BR.html.ftl by invite-email_pt.html.ftl and try it again. If not please check if in english is working properly (you need to user english language in your browser). I suspect the problem is pt_BR name.
Hello Diogo, try to create a rule on some temporary folder, choose Send e-mail action and choose to use template there. Then try to upload a document to that folder to see if you receive an e-mail. It is just to see if this works.
Meanwhile, if you can upload your alfresco.log somewhere, I could check if I can see anything else there.