The "Reply Timeout" error means that the Gamry Software has lost hardware communication with the instrument. The most common reason for this is the resetting of the USB communication chip inside the instrument, caused by a static discharge. To reset the instrument switch it off AND unplug the USB cable from the back. Ensure that the instrument is being used in an environment that meets the operating conditions laid out in the hardware manual. If it is possible, ground the chassis of the instrument as well. Furthermore, discharge yourself before handling the instrument and cell cables.
Another reason for receiving the "Reply Timeout" error is a communication interruption due to the use of excessively long USB cables and/or passive external USB hubs. The Reference Family instruments are rated and tested with a 6’ USB cable. Longer cables can work, but the quality of USB cables varies quite a bit and the additional length or a poor quality cable will cause issues with instrument communication. Likewise, connecting through a USB hub that is not powered can cause the same problems. For the best performance the instrument should be used with the provided 6’ USB cable, or with active USB cables and powered USB hubs, and high data rate devices (such as external hard drives and video devices) should not be on the same USB hub as the instrument.