All senders classfied as Bad reputation, Reject SMTP Connection for everything

Hi -

I have SMG 10.5.1-2 running on vmware.  Everything was working fine until 11am yesterday, when SMG started rejecting all email as bad reputation.

 The only way i have been able to get mail flowing thru SMG is to disable all options under reputation > bad senders.  How can i troubleshoot this problem?

thanks,

John