When I do failover between two devices,
incoming connections stay ok, and they don't make termination,
but outgoing connections from internal server through BIG IP devices breaks,
I can not find why, any one with same issue.
So you have a virtual server on BIG-IP that the internal servers are using to establish outgoing connections? Does that virtual server have connection mirroring enabled?
Forwarding VS's configured on both BIG-IP's?