BestHTTP Error : Ex [EventDescriptor]: Call - Message: Object reference not set to instance object

Hello, I am working on a networking game and I am using NodeJS as a server, socket.io as a communication channel between unity and node and I using BestHTTP asset from unity store and I am communicating using sockets now when I am connecting to socket I am able to get response and everything works just fine but this error comes up every time and I am not able to understand what is this error and how to solve it. anyone here helps me with this?