I can't find the setting how to configure the settings for emails sent to customers and also messages sent to me. How do I remove the marked lower part?
Do you have a web hotel or do you have your own server? The error log says nothing? You could try to install Joomla and see if emailing there works, just to compare.
Just wondering, has Prestashop any built-in newsletter sending function? Can't find any. I tried to send out via my web hotel but they have limited the service to 200 emails per hour.