AWS iot not working with esp32 espidf

[Anjusha]

During AWS IOT connection with esp32 in espidf I am getting the follwing error.

E (5239) aws_iot: failed! mbedtls_ssl_handshake returned -0x2700
E (5239) aws_iot: Unable to verify the server's certificate.
E (5249) subpub: Error(-4) connecting to xxxxxxxxxxxxwvia-ats.iot.us-east-2.amazonaws.com:8883

The AWS IOT configuration is working in arduino esp32,so that is valid also the certificates are valid as I am getting verify ok for openssl command.The certifcates are properly in folder /certs
aws-root-ca.pem
certificate.pem.crt
private.pem.key

Please provide solution for the issue asap.