Invalid LTI consumer response may result in empty error about ims-lti

[SidneyNemzer]

@lastmjs In my specific case, the LTI provider (which uses this library) sends the grades to the LTI consumer (which is another application that we control). The LTI consumer can extract the grade from the XML, but it doesn't bother with a valid LTI response (since both applications are only used internally). A valid response would be something like "got it, score recorded" (The actual response is detailed in the LTI specification of course).

But it's conceivable that you could get { [Error] message: undefined } by doing something else.

[lastmjs]

Funny, I think I just started running into this same problem. So are the grades sent back correctly? What does the error actually indicate?

[lastmjs]

Looks like my error was coming from the server returning a 500 response. A more helpful error message would have been very valuable