Cannot get vip secondary IPs to transfer over to other virtual appliance in AWS.

This is only a brief list as not back into work until next Tuesday where when I can test my F5 devices in AWS Assume you have added aws credentials to the F5 config

Check your default route. Which interface are you going out of API calls will be external to your networks so any access control lists will need to allow https to 0.0.0.0

Also check in AWS that each network interface with the secondary IP addresses has source/destination check disabled.

TCP dump on the command line monitoring the interface used for default routes should show calls to AWS when one of the F5 devices is taken offline. On an active standby pair of F5s you can make the active go to standby which should generate the API calls on the STANDBY F5 which then becomes the new active server