Yahoo mail will not come online with Sonoma. Any fixes?

I'm not sure you are setting up your email correctly to Yahoo. Your log shows you're trying to connect to a pop3 account at Frontier.com. First, remove the Yahoo account you currently have then do the following:

When you are creating the Yahoo account, Open Mail > Settings > Accounts. Click on the (+) sign and choose from the list, "Yahoo". Then fill in the account info as needed. IE - Your username or email address and then your password as an example.

If you want to use a IMAP account then follow what Randall_2023 stated. If you want or need a POP account that requires a special setup and Yahoo must generate the PW from their site under security settings. Let us know which.

I don't understand how that is possible. As far as I can see, it just won't work unless you put in username@yahoo.com. Frontier might be using yahoo servers for their email and forwarding but if you are trying to directly set up yahoo email, you'd need to use yourusername@yahoo.com. One way to test is it access yahoo email by going directly to Yahoo and try to log in. Just as a test. If it works in the web portal, then those are the credentials you need to use in Apple mail and use @yahoo.com

https://mail.yahoo.com

More on this topic. You've probably seen this but in case you haven't...

Here is Frontier's information on setting up email.

https://frontier.com/helpcenter/internet/how-to-use-frontier-email-on-computer

I see they call their email Yahoo but have a separate section for setting up Yahoo in Apple Mail.

You could try logging in their web server as shown called: (To test login name and passwords)

login.frontier.com/webmail

[Edited]

So now that we agree Frontier is using yahoo (but not yahoo.com), You should again remove this Yahoo account. Then add a new account and choose Other Mail Account. Put your credentials in and test. Then check the server settings again and it should offer you a way to set up all the settings per this:

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

If you don't see more settings by clicking on Server Settings, Click on the 'Outgoing Mail Account' item and then choose

'smtp server list' > Advanced.

Frontier only supplies the signal; Yahoo provides the email account.

The only way you would use frontier in your email address is if it's an actual Frontier email service as opposed to yahoo, gmail and etc.

Wow.....I was about to give up. LOL Glad it worked for you. Considered Solved?

I have Yahoo and no issues. Double check your PW and email settings.

Your email address in the Yahoo account should read your email name@yahoo.com. Not @ frontier.com.