It may help to see a screenshot of your account pane, your incoming server pane and your SMTP server pane.

Let me know if I am missing a screen shot you need to look at

My first observation is that port 587 is usually associated with authentication, such as STARTTLS (or maybe SSL/TLS - whatever works). Many email hosts want confirmation that this is a legit account. There may be more, but that is my first thought. This should be set for all of the SMTP server setups.

So it sounds like you want me to use STARTTLS as the authentication methgod in the outgoing SMTP. I changed to that & The email still bounced back to me with the following:

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

 louislyons@msn.com
   host msn-com.olc.protection.outlook.com [104.47.51.225]
   SMTP error from remote mail server after pipelined end of data:
   550 5.7.1 Unfortunately, messages from [216.154.220.159] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [AM7EUR03FT050.eop-EUR03.prod.protection.outlook.com 2024-01-31T19:06:17.823Z 08DC225BC7DEE090]

Well, the suggestion for STARTTLS was just my first thought, since it seems authentication is a likely problem and you are sending unauthenticated messages. The solution might be port 465 and SSL/TLS. I don't know the defined settings of your email provider, and even those may be wrong, as we see that issue daily. The error message is a wide one: 550 7.2.1 - more info at https://sendlayer.com/docs/error-550-5-7-1-unauthorized-email-rejection/ your email provider is on a black list, so I would start there. We have seen many posts where the sender's email address is self-hosted and does not have appropriate DKIM and/or SPF settings on the server -- something only the email provider can do or the account owner with direct access to cpanel.