Esp32 Aws Iot Data Missed while publishing and receiving

[mustray]

Hi,
I am working on ESP32 IDF-MQTT_3_1_1,using the subscribe_publish example modified to accept data via second uart.While publishing data (using Qos=0 or Qos=1) to the aws iot host, out of every 100 packets 4-10 packets are missed. Similarly when am receiving data on the subscribed topic, data is missed. What could be the possible reason.
Also my aws mqtt disconnects frequently. Any help is appreciated.