Mac Apple Mail 14.0, SMTP Server List is empty

Below is a Copy and Paste from Yahoo itself

Reference to link below

https://ca.help.yahoo.com/kb/SLN4075.html

IMAP server settings for Yahoo Mail

IMAP is the state of the art technology to connect your Yahoo Mail account to a desktop mail client or mobile app.

It allows 2-way syncing, which means everything you do remotely is reflected in your Yahoo Mail account no matter where or how you access it. Here are the settings you'll need to configure your mail client or app.

Incoming Mail (IMAP) Server

• Server - imap.mail.yahoo.com
• Port - 993
• Requires SSL - Yes

Outgoing Mail (SMTP) Server

• Server - smtp.mail.yahoo.com
• Port - 465 or 587
• Requires SSL - Yes
• Requires authentication - Yes

Your login info

• Email address - Your full email address (name@domain.com)
• Password - Generate App Password
• Requires authentication - Yes

If you are looking to download your email from Yahoo Mail into a third-party email app like Thunderbird, Outlook, or Mac Mail one time, see SLN28681 or if you need specific instructions for your mail client or app, reach out to its manufacturer.

https://ca.help.yahoo.com/kb/sln-sln28681.html

Download your email from Yahoo Mail with IMAP

Use the IMAP settings below to download your email from Yahoo Mail into a third-party email app, like Thunderbird, Outlook, or Mac Mail. For accounts with a lot of content, it can take several days or longer to download everything. If you need specific instructions to configure your app with our settings or to check the progress of your download, please reach out to the app developer.

We've updated our Terms of Service and Privacy Policy - You'll need to review and accept the new Terms of Service and Privacy Policy to allow third-party email apps to access your Yahoo Mail account. If you haven't already, sign into your account using a web browser to do so.

Then, use this info to configure your app

Incoming Mail (IMAP) Server

• Server - export.imap.mail.yahoo.com
• Port - 993
• Requires SSL - Yes

Outgoing Mail (SMTP) Server

• Server - smtp.mail.yahoo.com
• Port - 465 or 587
• Requires SSL - Yes
• Requires authentication - Yes

Your login info

If you're using Yahoo Account Key or some older email apps, generate an app password and use that for your account password.

• Email address - Your full email address (name@domain.com)
• Password - Your account's password
• Requires authentication - Yes

The previous reply was specific to " Therefore, I can neither verify nor edit my Yahoo! smtp server port number."

Interesting choice of words " which port to assign", the problem is that I am not given the ability in any way to either verify or change the port that has been assigned for me"

Then that is an issue to be taken up with the E-Mail Service to whom the User has chosen to use.

In effect, that specific issue is Controlled and Operated outside of the perimeter of the Apple Support Community Forums mandate which is to deal with Apple Technical Issues related to Apple Software, Apple Devices and Apple Services

Have taken enough of the Uses time

Good luck with this computer issue as it relates to Third Party e-mail Services