MUCH THANKS and credit to ScottH501 and LincKrakr for this fix..
I just tried it, and it worked for me!
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I dont have a yahoo plus account and got it to work using these settings.
Go to manual setup > IMAP account and change to these settings....
INCOMING
Imap server - imap.mail.yahoo.com
port - 143
security type - TLS (if available)
OUTGOING
SMTP Server- smtp.mobile.mail.yahoo.com
port - 25
security type - TLS (if available)
* check Require sign-in
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Now, under my "email" application, I have my gmail account and my Yahoo email account too.
This way, I don't have to go to my Yahoo email via a browser, and as trick202 mentioned, I will get notified on my phone when any new emails come in on my Yahoo (my primary email account.
Another "bug" on this otherwise awesome phone fixed!!!