The administrator cannot see traffic in the sniffer because it is being offloaded to the NPU (NP6). To view the traffic, offloading must be disabled so packets pass through the CPU.
B). config firewall policy ... set auto-asic-offload disable: This is the recommended method to troubleshoot specific traffic. By disabling ASIC offloading in the relevant firewall policies (Policies 5 and 17 in the exhibit), traffic is forced to the CPU and becomes visible to the sniffer.
C). diagnose npu np6 fastpath disable 1: This command temporarily disables the fastpath processing on the specific NP6 processor (ID 1) handling the ports. This forces all traffic handled by that NPU to the CPU, allowing the sniffer to capture it.
Incorrect Options: Option A uses invalid syntax (port-list disable is not a valid command). Option D (config system npu) is not the standard method for granular troubleshooting.

The diagnose debug authd fsso server command is the primary tool for troubleshooting communication between the FortiGate and the FSSO Collector Agent. This debug output reveals the status of the connection and the reasons for failure. The three most common connectivity issues identified by this debug are:
FortiGate cannot reach the IP address of the collector agent (Option C): The debug will show connection timeouts or "host unreachable" errors if the Layer 3 connectivity is missing.
The connection was refused / Port mismatch (Option B): If the FortiGate can reach the IP but the Collector Agent is not listening on the specified port (default 8000), the debug will display "Connection refused." This often happens if the port configured on the FortiGate does not match the listening port on the agent.
The pre-shared key does not match (Option D): If the IP and Port are correct, the next step is authentication. If the password configured on the FortiGate does not match the one on the Collector Agent, the debug will explicitly show an "Authentication failed" or "password mismatch" error during the handshake.
Note on other options: Option A (SSL) is less common than basic connectivity/auth mismatches. Option E (Group filters) relates to user processing logic, which occurs after connectivity is established.
Reference:
FortiGate Security 7.6 Study Guide (FSSO Troubleshooting): "Troubleshooting FSSO... Check connectivity (IP/Port) and authentication (Password)."

To determine the correct reasons for the adjacency failure, we must analyze the standard OSPF real-time debug output (diagnose ip router ospf all enable or diagnose sniffer packet) typically provided in this exam exhibit.
Analyze the Debug Output:
The debug output in this specific question scenario typically displays an incoming Hello packet line: OSPF:
RECV[Hello]: ... auth-type 0 ...
"RECV": Indicates the packet is coming from the Remote peer.
"auth-type 0": Indicates the Remote peer is sending "Null" (No) authentication.
Analyze the Failure:
The adjacency fails because the Local FortiGate is rejecting this packet.
If the Local FortiGate accepts "No Authentication", it would match auth-type 0 and form the adjacency.
Since it is failing (and producing a debug log), the Local FortiGate must be expecting a different authentication type (Type 1 Cleartext or Type 2 MD5).
Evaluate the Options:
A). The remote peer has either OSPF cleartext or MD5 authentication configured.
Incorrect. The debug shows auth-type 0 (No Auth) coming from the remote peer.
B). There is an OSPF authentication configuration mismatch.
Correct. One side is sending "No Auth" (Remote), and the other expects "Auth" (Local). This is a definition of a mismatch.
C). The local FortiGate does not have OSPF authentication configured.
Incorrect. If the Local unit had "No Auth" configured, it would match the Remote's auth-type 0, and the adjacency would come up. The failure implies the Local unit does have auth configured.
D). The local FortiGate has either OSPF cleartext or MD5 authentication configured.
Correct. Because the Local unit is rejecting the "No Auth" packet from the remote peer, it confirms that the Local unit has authentication enabled (expecting Type 1 or 2).
Conclusion: The breakdown of the OSPF negotiation shows that the Remote peer is sending no authentication (Type 0), while the Local FortiGate expects authentication, resulting in a mismatch.
Reference:
FortiGate Security 7.6 Study Guide (OSPF Troubleshooting): "Authentication mismatch is a common cause of OSPF adjacency failure. Debug commands (diagnose ip router ospf all enable) reveal the auth-type received versus expected." FortiGate CLI Reference: auth-type 0 = Null (None), auth-type 1 = Simple (Cleartext), auth-type 2 = MD5.