Hi Marcos,

John is mostly correct and provided a great article. Here is a link that also provides a good background on SSL -> TLS and STARTTLS: https://www.fastmail.help/hc/en-us/articles/360058753834-SSL-TLS-and-STARTTLS.  While there are some things that get negotiated under the covers (whether to use TLS and what version) and there is a port dependency for TLS versus a non-TLS connection versus STARTTLS, the built-in SMTPClient object has a property called EnableTLS which must be enabled/ set to True in order for a TLS connection to be made.

HTH...regards,

Mark

Hi,

Neither an expert. All I can say is that if you're using GMAIL, things lately have become a lot harder with Google and I switched to use a microsoft account for SMTP.

regards.

Hi, Marcos -

I am NOT an SMTP expert, but from what I read, the use of the STARTTLS command gets issued "under the covers" based on which port number is being used, so there's no setting or function in the SMTPClient object you can use to issue it. Here's a link to an article I found which may help explain STARTTLS:

    https://mailtrap.io/blog/starttls-ssl-tls/

Best regards, John