cURL error 60 SSL certificate problem

I’m getting the following error when I access Depicter’s to dashboard, on my website:
“Oops! An issue has occurred while activating this website. Please try again, and if the problem remains contact us.
: unable to get local issuer certificate (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for https://wp-api.depicter.com/v1/client/validate/activation!”

The page I need help with: [log in to see the link]