[Email] Getting "failed to update headers" error on sub email account

Anyone else recently started getting "failed to update headers" error on their Yahoo sub email account(s)? Have a sub email account (@sbcglobal.net) that in the past few days is generating a "failed to update headers" error message ever time Outlook 2010 accesses the account to receive email. Main @sbcglobal.net email account works fine, no errors. Not seeing anything in Googling that would point to this problem or a solution to it. Both main account and subaccount incoming/outgoing servers/ports the same.