inherited a exchange 2013 setup that's labeling incoming email as "Forward report: 5.7.5 (Cryptographic failure)". The email makes it to the user as a attachment. The senders are from hotmail.com, sbcglobal.com, and other big email providers.
The forward message says
"Reason: Cryptographic failure
A transport system otherwise authorized to validate or decrypt a message in transport was unable to do so because necessary information such as key was not available or such information was invalid.
Additional info:
The message has an invalid DKIM-Signature"
Is there a way to disable this and just receive the email directly?