copy sent mail to sent folder

Your script sends through SMTP from a Comcast mailbox, but SMTP submission does not provide PowerShell a standard way to place a copy in that mailbox’s Sent folder. The Sent folder belongs to the mailbox service, so the server must offer it or the message must be sent through a mailbox API. First, test the same Comcast account in webmail and confirm whether it saves a Sent copy; that separates mailbox behavior from the script. Do not rely on a local Outlook Sent folder unless Outlook sends the message. If the mailbox is Microsoft 365 or Exchange Online, move the send operation to Microsoft Graph: its send-mail operation saves to Sent Items by default unless disabled. If this must remain Comcast SMTP, check Comcast’s documented SMTP settings or support options; otherwise archive a copy separately, because Windows PowerShell 5.1 cannot force a remote provider’s Sent folder to accept one.