Not able to connect Mosca SSL Server with ESP32

[kd.spide]

Mosca SSL Broker is working fine with mqtt client.But ESP32 not connecting to it.
const esp_mqtt_client_config_t mqtt_cfg = {
.uri = "mqtts://192.168.43.187",
.port = "8883",
.event_handle = mqtt_event_handler,
.cert_pem = (const char *)ca_crt_start,
.transport = MQTT_TRANSPORT_OVER_SSL,
.lwt_topic = "Death",
.lwt_msg = "Device is Disconnected",
};
this is the config.
and output is
I (3107) event: sta ip: 192.168.43.114, mask: 255.255.255.0, gw: 192.168.43.1
I (3107) MQTTS_SAMPLE: [APP] Free memory: 239004 bytes
I (3107) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
E (3127) TRANSPORT_SSL: mbedtls_net_connect returned -44
E (3127) MQTT_CLIENT: Error transport connect
I (3127) MQTT_CLIENT: Reconnect after 10000 ms
I (3137) MQTTS_SAMPLE: MQTT_EVENT_DISCONNECTED

What can be the possible reason?

I am using https://github.com/tuanpmt/espmqtt/