unable to delete SMTP Mail server

My email company changed the configuration for their Servers.

I was able to add a new SMTP server, but I cannot delete the old ones.

Using Mac Mail 11.3

The steps I followed are below. When I click on the minus icon, the server disappears. I then close the preferences page. If I open the preference page again the supposedly deleted server has returned. I have tried quitting mail and even rebooting the computer, but the zombie just will not go away.

1. With Mail open, navigate to the Mail > Preferences... menu item.
2. Go into the Accounts tab.
3. From there, open the Server Settings tab.

   Note: If you're using an old version of Mail, you will not see this option. Just skip down to Step 4.

4. Next to "Outgoing Mail Account:", click/tap the drop down menu and choose the Edit SMTP Server List... option.

   Note: Some versions of Mail might call this the "Outgoing Mail Server (SMTP):", and the option Edit Server List....

5. Select an entry and choose the minus button toward the bottom of the screen, or pick an option called Remove Server if you see it.
6. Depending on your version of Mail, hit the OK or Done button to return to the previous screen.
7. You can now exit any open windows and return to Mail.