I don't know if this is the cause or not, but recently Yahoo changed their email server config which is related to hamper most mailing lists. There was a right up about it on Slashdot here:

http://tech.slashdot.org/story/14/04/09/2047205/yahoo-dmarc-implementation-breaks-most-mailing-lists



Jim McCorison
Orcas Island, WA

On Apr 13, 2014, at 9:23 AM, Milton Hywatt <mhywattt@yahoo.com> wrote:

Yahoo has been having issues with their POP servers and
I guess a lot of list messages have been bouncing because
I had to re-enable my account So if this keeps up, I thought
it was fixed because I was getting email fine yesterday I
will have to choose gmail to receive my list messages.
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