Runtime Error: Error from Companion

I have follow error:
Error from Companion: Attempt to invoke virtual method 'java.lang.String java.lang.Throwable.toString()' on a null object reference.

How do I find out exactly where the problem is?

Show your relevant blocks where the error occurs. This is the only way to tell why you have an error.

Are you using any extensions or hust native components?

i got the same problem, it suddenly popped up a notification as the mentioned.
What should i do to generate the next screen after waiting for a while?

Have you updated your companion app to the latest version: 2.66 or s.66u ?