I run the script for the first time but getting Error as NL-NETWORK-01 & Msg: An IO Error occured sending the request?

I am using NeoLoad 5.3 version. When I run the designed neoload script for the first time, I am getting Error code: NL-NETWORK-01 & Msg: An IO Error occured while sending the request for all the request in the script. I also tried with the option of using the same neoload certificate for recording and replaying, but it did'nt worked. Please find the attached screenshot of error msg.