Unable to get local issuer certificate

• curl: SSL certificate problem: unable to get local issuer certificate
• openssl s_client -showcerts -connect: verify error:num=20:unable to get local issuer certificate

 curl -v https://google.com
 * processing: https://google.com
*   Trying 142.250.181.78:443...
* Connected to google.com (142.250.181.78) port 443
* ALPN: offers h2,http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
*  CAfile: /etc/ssl/certs/ca-certificates.crt
*  CApath: /etc/ssl/certs
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (OUT), TLS change cipher, Change cipher spec (1):
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* TLSv1.3 (IN), TLS handshake, Server hello (2):
* TLSv1.3 (IN), TLS handshake, Encrypted Extensions (8):
* TLSv1.3 (IN), TLS handshake, Certificate (11):
* TLSv1.3 (OUT), TLS alert, unknown CA (560):
* SSL certificate problem: unable to get local issuer certificate
* Closing connection
curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: https://curl.se/docs/sslcerts.html

curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.

SSL: OpenSSL, LibreSSL, wolfSSL, BoringSSL, SSL pinning, /etc/ssl/certs/, ca-certificates, /etc/ssl/, sslscan2