X509: certificate signed by unknown authority CMD K6.io

I am presently using a nice tool to perform performance testing (load) for a project via a VPN. I am using K6 and SOAPUI. run the same tool using both tools just to compare results. K6 is a Javascript library that gathers robust configurable metrics, and likewise SOAPUI. The challenge is that SOAPUI works smoothly while K6 always hit a certificate issue. Since SOAPUI works fine I believe the problem is either certificate issue with my system or K6.io. I’m yet to figure out what the real problem is.

The main reason why I like k6 is because of the robust reporting tools it integrates with like InfluxDB and Grafana. It is because I have to generate graphical reports for the test.

Error from k6.io CMD

script: AccountClosure.js
     output: -

  scenarios: (100.00%) 1 scenario, 1 max VUs, 10m30s max duration (incl. graceful stop):
           * default: 1 iterations for each of 1 VUs (maxDuration: 10m0s, gracefulStop: 30s)

WARN[0002] Request Failed                                error="Post \"https://mysite.behindvpn.com:4333/fiwebservice/services/FIPWebService\": x509: certificate signed by unknown authority"
running (00m01.8s), 0/1 VUs, 1 complete and 0 interrupted iterations
default ✓ [======================================] 1 VUs  00m01.4s/10m0s  1/1 iters, 1 per VU

Sorry I posted too early without searching enough. I found the answer on this link