mqtt-exception : ssh handshake failed with openssl error - SSL_ERROR_ZERO_RETURN

HI Team,

I had provisioned MQTT "**eclipse-mosquitto**" docker on AWS+NLB for the MQTT broker and used MQTTnet for the communication to mqtt broker, client services are running in the same AWS region as docker container which is using "**mcr.microsoft.com/dotnet/core/aspnet:3.1-buster-slim**".

Everything is working fine without TLS option, but when I enabled TLS (MQTTS) for the communication getting open SSL error "SSL_ERROR_ZERO_RETUN".

- Network Loadbalancer provides the TLS certificate for the TLS communication between client and loadbalancer but loadbalancer and mqtt broker communication is HTTP only.
- Update FQDN CA certificates into client docker images.
- I have tested MQTT CLI client tool, it was working using TLS.