The data required for the configuration of an email client for an @alumnos.upm.es or @upm.es address can be found at:
UPM Student Email Configuration
UPM Personal Email Configuration
There are also published some guides of the most common customers.
Clarify for Configuration:
The SMTP part must be configured with authentication and security: Port 587, with STARTTLS authentication and security. Configurations with port 25 are not valid.
For authentication, the same username and password as the entry access password must be used, but complete; that is: nombre.apellido@alumnos.upm.es nombre.apellido@upm.es
Access to mail is also possible via a browser via the gateway
Finally, you can always contact the IT staff of your Center to request more direct support.