If I'm still getting a 403 error after providing a client certificate in Postman, what troubleshooting steps should I take?

First, double-check the certificate's validity (expiration date, issuer, and if it's been revoked). Verify that the domain specified in Postman's certificate settings matches the exact domain of the API endpoint. Confirm that the certificate's passphrase (if any) is correct. Review the server's logs for detailed error messages related to certificate verification. Try using a different client certificate if available. Finally, consult the API documentation or server administrator for specific certificate requirements.