Hello, Prabh.
Your answer lies in the info you provided:
domainkeys=neutral (no sig); from=digital-infotech.net; dkim=permerror (future timestamp)
Yahoo appears to think that your timestamp is off by some amount of time in the future.
-- Mike Burger http://www.bubbanfriends.org
Configured NTP, restarted server, sent new mail and i have.
Authentication-Results: mta1217.mail.mud.yahoo.com from=digital-infotech.net; domainkeys=neutral (no sig); from=digital-infotech.net; dkim=permerror (future timestamp)