Some Guidelines of the yahoo mail getting bounced -
Hurray has upgraded the DMARC record with "p=reject" for the "yahoo.com," "ymail.com," and "rocketmail.com" spaces.
This implies all DMARC agreeable mail collectors (counting Hurray, Hotmail, and Gmail) are currently skipping messages sent as "@yahoo.com" locations that aren't sent through Yippee servers. Any messages without a legitimate Space Keys Distinguished Mail (DKIM) mark or Sender Approach Structure (SPF) arrangement will be dismisses.
ESPs who utilize their clients' "@yahoo.com" address as the "From" location to send messages are affected by this change.