Bug with always getting exception "UNKNOWN: Response stream closed without gRPC status"

[JustFeitan]

We have various exceptions on our backend, I only get the error "UNKNOWN: Response stream closed without gRPC status" (screen attached). But at the same time I receive headers with required information, which are sent to me from the backend, but i can't access the using onHeader option
Exception:

Network(1):

Network(2):

[aikoven]

After some investigation we figured out that the reason was that the server didn't send the correct Access-Control-Expose-Headers CORS header.

The problem went away after we set the server to return Access-Control-Expose-Headers: *.

As a resolution to this issue we will update the error message to mention it.