Emails being send through Symantec Messaging Gateway (SMG) via Content Encryption (CE) are failing SPF checks when reaching the recipents.
The SPF record of the sender does not include the IP(s) used by CE.
Add the following include statement to your SPF record:
include:spf.z118.zixworks.com
Add the following include statement to your SPF record:
include:spf.messagelabs.com