Issue:
You’re getting this PHP error when connecting to an HTTPS endpoint (like PDF.co):
SSL certificate error: unable to get local issuer certificate
This error happens because your PHP environment cannot locate the certificate authority (CA) bundle needed to verify SSL certificates.
How to fix it
Recommended solution:
Follow this step-by-step guide on StackOverflow with multiple proven fixes: See Solutions on StackOverflow →
The solutions include:
Downloading and configuring cacert.pem
Updating PHP’s openssl.cafile or curl.cainfo setting in php.ini
Restarting your server after updating config
Helpful tips:
Make sure your PHP environment is up-to-date.
Test the connection using curl or openssl CLI to check if it’s PHP-specific.
This issue is related to local server SSL configuration, not PDF.co’s servers.