When a Replica appliance is replaced, it may not go into "Replication" mode automatically.
1. Put the Primary in "Standalone" mode on the Primary's /paradmin interface, HA Settings page:
System Status/Settings | HA Config | HA Settings
2. Take a backup of the Primary:
/paradmin interface, Backup | Backup Now, and copy the backup to a locally accessible location.
3. Restore the backup to the Replica from the /parconfig interface on the Replica itself:
Restore | Restore Appliance
If the Replica is not in Primary mode, use the https://IP_of_Replica:8443/parconfig/forcereplica.asp page to force the Replica into Primary mode. Wait for the restore process to complete
4. Put the Replica in Test mode.
5. Wait for the Replica to be running in Test mode.
6. Put the Primary in Replicating mode on the Primary's /paradmin | System Status/Settings | HA Config | HA Settings page.
7. Watch the HA logs.
8. When first DR backup is successfully pushed across, put the Replica in Replica mode on the Primary's /paradmin | System Status/Settings | HA Config | HA Settings page.
Refer to the below KB for more information on forcing mode changes:
Troubleshooting an issue when the Replica status shows as "Unknown". (75497)