Messaging Whatsapp end chat by itself

Hello Community,

recently i'm developed some messaging whatsapp inbound on my org.

long story short setup and the numbers it's configured perfectly, and i can chat with an agent.

but sometimes, when i'm in the middle chat with a customer, my session is ended automatically.

if it from unstable connection from me (agent) i can understand that, my connection is stable.

and i'm sure im not setting anything about 'auto end chat' when develop this.

i just want to know, is it common the session is ended by itself? or  there's another reason for why this happened? 

Thanks.