When troubleshooting problems related connection timeout on Cisco ASA, there are few things necessary to look at if need investigate in more details. Such as TCP handshake messages below. You may have Syslog enabled on the firewall which may provide you clue of what is actually going on. But having a look at the Firewall in real time to provide you open or active or inactive TCP or even UDP session.
Take a look at the each flag and root cause the time outs.