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.
We can't see the whole error from your screen shot but it seems related to your client certificate.
Do you need a client certificate to reach your application? If yes is it the one that you loaded in the NeoLoad preferences? What is its format?