XG Active Passive HA Cluster Not Working

Question

I have two XG210's that I am attempting to configure in Active/Passive HA. I followed the instructions here: https://community.sophos.com/kb/en-us/123174 
 The firmware on both is 17.03 M3 
 I configure all the settings and it syncs successfully, however it immediately breaks the network. Most VPN tunnels crash immediately and we have intermittent connectivity to the internet. 
 The HA link port on both is port 6 - Both are on the dmz zone and SSH is enabled from dmz 
 Is there something I am missing which could be causing the behavior???

Joe Plunkett · Answer

All ports and connections were correct. Spent two hours with support but figured it out. Even though the Secondary device was configured correctly, it was STUCK in primary mode. This device was brand new and had never been set this way. Just a weird quirk that it became locked in this state. We had to factory reset and then it all worked correctly.