I have faced an issue with a Laravel backend which is trying to make an HTTPS request to another service, and by checking the logs I have found this error.

[2021-05-20 02:16:53] production.ERROR: cURL error 77: error setting certificate verify locations:
  CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) {"exception":"[object] (GuzzleHttp\\Exception\\RequestException(code: 0): cURL error 77: error setting certificate verify locations:
  CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) at /www/wwwroot/backend/vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php:201)
[stacktrace]

I’m using Ubuntu server 20.04.2 LTS with PHP 7.1 installed.

And here you are what I made to solve the issue.

sudo apt-get install ca-certificates

This package includes PEM files of CA certificates to allow SSL-based applications to check for the authenticity of SSL connections.

sudo mkdir -p /etc/pki/tls/certs

 This will create folders for the target destination if they do not exist.

sudo cp /etc/ssl/certs/ca-certificates.crt /etc/pki/tls/certs/ca-bundle.crt

Finally, copy certificate to the expected destination.