@Manish Vishnoï Thanks for reaching and apology for the inconvenience due to this issue. As per the error it looks like you are facing an issue with the SSL handshake between Envoy proxy and your application's HTTPS endpoint. The error message you are seeing is usually related to the connection between the proxy and the backend service.
One possible reason for this error could be that Envoy proxy is not able to trust your application's self-signed certificate. To make Envoy proxy trust your application's self-signed certificate, you can add the certificate to the trusted CA list of the proxy.
In case if you are still facing the issue or resolved the issue then please let me know so we can assist you further or it could be of benefit for other community members facing the similar issue.