I see you have a throttling rule in 'quotas' table: 20 messages in 60 seconds.
1) if no record in table 'quotas_tracking', that means your testing email doesn't match both sender and recipient defined in table 'policies' (ID=2, name="Default Outbound").
2) Policy 'Default Outbound' defines email must be sent from an internal IP address (defined in sql table "policy_group_members") or sender must be an internal domain (Source='%internal_ips,%internal_domains'), and recipient must be an external domain (Destination='!%internal_domains').
So, my question is, what's the sender and recipient in your testing email? Was it sent from an internal IP address?
Could you please turn on debug mode in Cluebringer config file, restart Cluebringer service, send a testing email, and paste full log of this smtp session here to help troubleshoot?
# File: /etc/cluebringer/cluebringer.conf
# OS: Debian/Ubuntu
log_level=4
log_detail=modules,tracking,policies