Hi Tim,
This sounds like an issue in the underlying fetch implementation, see here:
https://stackoverflow.com/questions/34656412/fetch-sends-lower-case-header-keys
I would be more than happy to publish an update to the app store module that addresses this by using XMLHttpRequest or some other method if someone is willing to share their code with me.
Hi Tim,
I released an update to the app store that addresses the issue. https://appstore.home.mendix.com/link/app/112178/
Let me know if everything works ok.