Hi Sergio,
Welcome to the Forum.
For forum users to be able to assist you it would help if you told us which email client you are having trouble with in Windows 10 when attempting to send emails.
- Windows 10 Mail
- Windows Live Mail 2011
- Windows Live Mail 2012
- Thunderbird
- Outlook
Which one is giving you the problems?
Also, have you verified the Email settings are correct for the ISP you receive internet and email from? For example are they using IMAP or POP and SMTP protocols? Do you have the correct send port open. Many ISPs offer two choices for the send port for example.
Regards,
Regedit32