Information
Ensure a High Availability peer is fully synchronized and in a passive or active state.
    Rationale:
    To ensure availability of both the firewall and the resources it protects, a High Availability peer is required. In the event a single firewall fails, or when maintenance such as a software update is required, the HA peer can be used to automatically fail over session states and maintain overall availability
Solution
Navigate to Device > High Availability > General.
    Click General. Click Data Link (HA2). Select the correct interface . Select the protocol (IPv4 or IPv6). Select the correct Transport. Set the Enable Session Synchronization box to be checked.
    Save Configuration.
    Default Value:
    Not Configured