FTD node fails to start and there are errors in Admin UI under Administration -> System Management -> Cluster. Restarting cluster, FTD or even rebooting the appliance does not help.

This could be caused by deviation of default ports of the node(s) - go to Administration -> System Management -> Access Points:

  - Local Network: default port range 8090-8094

and/or

  - Internet: default port range 8095-8099

EXAMPLE:   Local Network port range is set to a single port 8091-8091.

SOLUTION:

1. Restore default setting
2. Reboot the appliance
3. Now node(s) should have no problem to start and there should be no errors under Administration -> System Management -> Cluster.