MQTT Error Code 7 - AMQJS0007E Socket error: Unknown socket error

I'm trying to use one Client (Mobile App) to subscribe to multiple topics at the same time. It works at first but then it keeps disconnecting my previous subscribed topics and shows this error message "AMQJS0007E Socket error: Unknown socket error". Instead, I want all the connections to be alive so I can receive real-time data instead of keeping reconnecting all the time.

Please help me resolving this issue.

Thank you.