Can't get Apple Mail working with the new Yahoo account.

Unsure what you've done here but for years I have had no issue with accessing my Cox Email.  Then the decision is made to remove this service from your offerings which is fine.  But in doing so you have left a huge hole in your support model.  So here's what has happened...

I received the notification to transfer my account.  I did this successfully except I cannot use Apple Mail to access the account any longer.  I have tried all sorts of settings, added, removed, edited the setting on  Mac OS to get the my Apple Mail to download my email to no avail.  I can use Yahoo webmail but I want it to work the way it did before.  I can get a regular Yahoo account to work with Apple Mail but not whatever you've devised here will not.

I expected better from Cox.