Dear Khun Pornchai,
Could you please follow as this step for verify and fix this issue.
1. Check your servers to make sure that Flow Control is not enabled. Please note that Flow Control is disabled on HP ProCurve switch ports by default.
2. Next, ensure that the NICs provisioned within the servers, and the ports of the switch, are allowed to Auto-negotiate.
3. Also, ensure that the software revision of the switch is current, as well as the drivers or firmware of the server NICs. Finally, check cables and the hardware of the servers’ NICs to ensure they are supporting the maximum possible bandwidth.
4. In short, if a device connected to a switch port is too busy to receive the packet flow coming from the switch, then their buffers may overflow, causing the switch to retain outbound packets. The switch will repeatedly attempt to forward the packet unless the downstream device is so busy that the traffic’s TTL runs out. When a packet’s TTL expires, a switch will drop the packet and log a "Drop transmitted" or "Drop Tx". For more information on ensuring the overall health of your network, please review the white paper titled, Troubleshooting LAN performance and intermittent connectivity problems at http://www.hp.com/rnd/library/troubleshoot_lan.htm.