HTC Evo Mail app will not receive yahoo! mail beta emails?

I have an HTC Evo phone and use yahoo mail as my main email account. I have had the mail app provided on the Evo set up to display my yahoo email using the imap/smtp. It has been working with no problems, until today. I am no longer receiving any new yahoo emails ( I can still send ), but if I log in to my yahoo account via the internet I have new emails. The only thing that has changed is that I updated my yahoo mail to use the new Yahoo! Mail Beta. To run a test, I set up a gmail account and another yahoo account that has not been converted over to the new Beta. They are both working fine and I am able to receive and send email. I have tried deleting the account and recreating and all that did was loose all my old emails also. Still cannot receive new emails. I went to the yahoo! mail beta website and tried the imap and smtp settings specified for an android device, but that did not have any affect. Has anyone else encountered this issue or have any ideas on how to fix.