curl: (60) SSL certificate problem: unable to get local issuer certificate
Solution 1:
Becase curl is unable to verify the certificate provided by the server.
There are two way to bypass:
1.add -k option which allows curl to make insecure connections, which does not verify the certificate.
2.add root curl ca (download here) to /etc/ssl/certs/nodesource-ca.crt
Solution 2:
Or, for me, worked simply this:
sudo apt-get install ca-certificates