No salen los mail y aparece un recuadro
What is the error you are getting Daniel?
Some things you can try are to disable your anti-virus and try again. Or check that you have the correct port and security protocol settings.
Port 587 = Force usage of SSL/TLS
Port 25 = Use SSL/TLS if available
Port 993 = Use SSL/TLS on special port (legacy)
Port 143 = Use SSL/TLS if available
Port 995 = Use SSL/TLS on special port (legacy)
Port 110 = Use SSL/TLS if available
These are the correct combinations of port and security policy. The underlined ones are the best option for security if your server supports them, so try those first. SMTP port 465 was reassigned and should no longer be used for SMTP, though many mail providers still recommend and use it. If you want to use port 465, the security policy should be set to Use SSL/TLS on special port (legacy)