JSON value '' of type NSNull cannot be converted to NSString

I am getting the following error screen sometimes when I reload my React Native app in iOS Simulator.

Sometimes it doesn't happen at all but sometimes a few times during the day.

I am using SignalR client in my app as well as Firebase Messaging.

I have tried to put a try catch blocks to all of my app including where I use AsyncStorage but this is still happening.

Very frustrating.