HA Pair is Active / Active and In Sync

Looks like it is either the devices don’t trust each other or they cannot communicate the configured Failover VLAN and IP addresses.

You can test connection from the command line, under Bash SSH from bigip1 to the failover address configured on bigip2. If this work both ways connection should be good. If not double check network configuration and the SelfIP port security config is set to Allow All.

Once happy with connection setup the trust again, on bigip1 go to Device Management > Device Trust, and then Peer List.

Click Add and use the failover IP address of bigip2 and admin username and password.

You may find you need to remove bigip2 from the Device Group and delete it as a trusted peer before doing this.

Let us know if that works or not.