Hub is showing a cURL error 60: SSL on one of my sites

I’ve installed Defender on one of my sites and I’m seeing this error when checking my sites from Hub, under the Security tab:

cURL error 60: SSL certificate problem: unable to get local user certificate

The error is there since the plugin was installed. Also, I just recently set these sites up on Amazon lightsail and I've tried adding the curl.cainfo =, with no luck.

Just another note, if I try to activate uptime, I get an error. The exact error is: "Your domain does not appear to be publicly accessible on the Internet. We can only monitor the uptime of public websites."