setting the Cisco cml Traffic generator

I am using Cisco cml version 2.2.3. currently, I would like to use the Trex (traffic generator) of the Cisco cml. However, the TRex GUI is getting the following error >>> "error while verifying async request: no response from server"

I want to solve this problem and the TRex can work.
Note: please only people who are able to solve it communicate with me.