Carbon Copy Option When Sending Emails Not Functioning

In the last 2 weeks, both Yahoo and AOL have made changes to their DMARC email policies.

These changes affect the delivery ability of emails sent to and from Yahoo and AOL accounts.

Here is the technical explanation of what the changes are:

https://help.yahoo.com/kb/postmaster/yahoo-dmarc-policy-sln24050.html?impressions=true
All DMARC compliant mail receivers (including Yahoo, Hotmail, and Gmail) are now bouncing emails sent as "@yahoo.com" addresses that aren't sent through Yahoo servers. Any messages without a proper Domain Keys Identified Mail (DKIM) signature or Sender Policy Framework (SPF) alignment will be rejected.

http://postmaster-blog.aol.com/2014/04/22/aol-mail-updates-dmarc-policy-to-reject/
Mail sent on behalf of AOL Mail users to DMARC-compliant domains will be rejected by those domains unless the mail passes SPF and/or DKIM authentication checks AND the domain(s) used in those checks match aol.com.

Unfortunately, we cannot control changes to the Yahoo and AOL infrastructures and policies, therefore we cannot prevent this issue from happening.

However, we do recommend switching to another email provider or a corporate email account (ie. Gmail, or something similar)-- this is something you can do yourself ( http://www.google.com/enterprise/apps/business/ )

or if you need assistance we would be happy to help you for a fee.

We apologize for any inconvenience this may cause.