Hi Surenderreddy Konatham,
This may happen if your Azure function's Authorization level is set to Function or Admin which would require inReach Portal Connect to send authentication credentials with each request. If this is required it may be possible for you to implement that but I do not know what would be required to do so.
Switch auth level to Anonymous by going to Integrate settings in your Azure function:
then set Authorization level to Anonymous:
and click save.
Also, I found and corrected an error in my code so please update your function. While verifying this behavior this morning I noticed I had left off a rather important element to the feature json that gets sent to the feature layer - spatialReference (DOH!!!). InReach sends data in WGS84 (wkid 4326) while ArcGIS Online feature layers use, by default, web mercator (wkid 102100). If incoming features include spatialReference info other than web merc, the feature layer will project them correctly to web merc and store them. Otherwise it assumes the features are already in web merc and does nothing to the geometries resulting in incorrect placement for inReach features.
I have updated my code on GitHub.
Ken