WiFi Sync error code 0 and server doesn't get the request - what should I do (it works fine in the Simulator)

Hello,

I am trying to develop an App for my Garmin Venu 2 that allows me to input some Text via the Keyboard, which then gets sent to a Node-RED "http in"-node for further processing.+

I want to do so over the Venu2's built-in WiFI because my connection to the phone isn't reliable enough for this.

When I try things out in the Simulator, everything works and the Request gets sent and received properly.

When I now sideload the app to my physical Venu 2, it first apperas to work fine, connects to the WiFi, but then the error code 0 appears.

My server also doesn't receive the request then.

Here's my source code:

https://drive.google.com/file/d/1HOFMuIsnZ-fVPhog9W0Il1p3ZimsebL7/view?usp=drive_link

Thanks in advance

Aaron