Oulook pop3

For over a week now I have not been able to down mail from Yahoo to Outlook. I get the following error,

Task 'deleted by moderator - Receiving' reported error (0x800CCC0F) : 'The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP).'

I can successfully test account settings and send email. However, repairing the account will not automatically retrieve yahoo account settings.

This happened on both my laptop and my desktop at the same time. I am running only Windows defender on the Desktop and McAfee on the Laptop. I have done the following things to resolve this issue.
1. Clean Boot
2. Start Outlook in Safe mode.
3. Temporally disable all firewalls and virus scanning.
4. Run scanpst on pst files.

About one day after I stopped receiving mail, I received this email

From: YAH00!! [mailto:mimiaziza@aol.com]
Sent: Thursday, May 21, 2015 2:32 AM
To: deleted by moderator
Subject: Security Protocol

Dear Account Users,

Some unusual activities have been detected due to security protocol,
You have reach the storage limit and cannot send or receive new message until you verify your mail box.

ACCOUNT VERIFICATION

Your mailbox will not be affected and you will keep all your old contact folders and message

Thanks
Yahoo Team

So how did these folks know that I could not receive email? Do you have any suggestions how I can restore my ability to receive Yahoo mail by POP 3? IMAP works fine. Mcaffee and WIndows defender full scans report nothing