I have a problem with my FTDv 7.3.1 on ESXi. When I start uploading a large file over L2L VPN using SCP or SFTP between the server and the remote host, after a while the outside FTDv subinterface becomes unavailable and IPSec is aborted. After a few minutes, the subinterface becomes available. I tried it many times and always I got this problem. I tried restarting FTDv and the problem was fixed after that, but I don't know if it will come back again. What can I do to find the cause and fix it?