ERROR: Registering runner... failed Installng "Gitlab runner" PANIC: Failed to register this runner. Perhaps you are having network problems

I'm trying to install GitLab runner sudo gitlab-runner register in Ubuntu 16.04 getting error

ERROR: Registering runner... failed   runner=pcT3WTf5 status=couldn't execute POST against 
http://gitlab.com/api/v4/runners: 
Post https://gitlab.com:443/api/v4/runners: x509: certificate signed by unknown authority  
PANIC: Failed to register this runner. Perhaps you are having network problems 

GitLab runner version:

root@user-VirtualBox:/home/user# gitlab-runner -version
Version:      13.2.2
Git revision: a998cacd
Git branch:   refs/pipelines/172580057
GO version:   go1.13.8
Built:        2020-07-30T14:51:44+0000
OS/Arch:      linux/amd64

Thanks in advance