Thank you for your question.
First of all, please next time provide us with more details regarding your product (e.g.: firmware version, server version, …). Thanks to that our community will be able to answer you better and to learn from it.
As you didn’t provide many information it is difficult to state what is the cause of the failure. It could be everything from devices to servers.
Please try to use the USB key locally on the device. If it works locally the problem is not on client side (it is not a hardware problem).
You didn’t mention which firmware version or which version of the farm you use. I suggest you to use the latest version of the Teradici firmware.
I don’t know if the problem is only on some devices or on all of them. If the problem occurs on all the devices probably the problem in on the server side.
Another suggestion is that if the infrastructure was working and then you changed something on the server side then probably what you changed is the cause of the problem.
I hope this answered your question.