LTI 1.3 Deep Linking: "Invalid signature validator"

[jarettive]

I'm trying to integrate our learning app with the LTI Advantage Deep Linking service in Schoology. When trying to post the form for the DeepLinkingResponse JWT after going through Course Material Selection, we receive the following error:

{"error":"handleDeepLinkingLaunchInfo.error: Invalid signature validator."}

And no material is created. This error only happens with our production environment. When using our app on localhost it works fine and I'm able to successfully create working Materials in Schoology via Deep Linking. 

Does anyone know what this error means? Or even better, does someone know how to get in contact with the developers who know about the LTI 1.3 integration? 

[mclaassen]

Not sure if you got this figured out yet or not.

When I read this, the first thing that came to mind so the "kid" field in the JWT header.  This value needs to match on of values returned from your JWKS endpoint.  You are probably using different keys in development.

If I can ask you a question, does your localhost testing still work?  I am getting a 403 when I try to test on localhost now.  I am not sure when this stopped working.

If localhost does still work for you, do you also specify a port number?  (e.g. https://localhost:3000)

(I am trying to figure out what I can do to get localhost working again.)

Thanks!