GitHub - jeremydumais/CPP-SMTPClient-library: A simple SMTP client library built in C++ that support authentication and secure connections (Forced SSL and Opportunistic SSL/TLS encryption)
![SMTP Client Supporting Implicit SSL Secure Sockets Layer with OAuth2 Open Authorization or Password Authorization (2.0) - CodeProject SMTP Client Supporting Implicit SSL Secure Sockets Layer with OAuth2 Open Authorization or Password Authorization (2.0) - CodeProject](https://www.codeproject.com/KB/IP/1173678/TestUziSecureSmtpClient.png)
SMTP Client Supporting Implicit SSL Secure Sockets Layer with OAuth2 Open Authorization or Password Authorization (2.0) - CodeProject
GitHub - meetakbari/SMTP-Protocol-in-C: ECommun - A C based SMTP Protocol Implementation using Socket Programming
![powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow](https://i.stack.imgur.com/xgAb5.png)