Configuring the outbound firewall rule to permit traffic on port 3237 is the additional action that resolves the issue. AMP file reputation is a feature that allows Cisco ESA to check files attached to messages against a cloud-based database of known malicious files and apply appropriate actions, such as block, deliver, or quarantine.
By default, AMP file reputation uses TCP port 3237 to communicate with the cloud-based database. If this port is blocked by a firewall, AMP file reputation will not work properly.
To resolve this issue, the administrator can configure the outbound firewall rule to permit traffic on port 3237 from Cisco ESA.
The other options are not valid actions to resolve the issue, because they do not affect the port used by AMP file reputation.