Communication Generation

We are currently trying to run Communication Generation to send out email notifications and it appears to be completing successfully, but it won't process any communications.     When looking at the trace file it has the following message:

Person Communication ID: ######## missing critical data. (14100,856)

If we choose to process the communication if critical data missing, an email will go out to the recipient (me).      We have the communication set up with the admin function as 'GEN'

With this communication sent to me, I know I have all the name/address info data.     The missing critical data message is vague as it does not tell one what the missing critical data is.