My application utilizes a few REST API endopints using HttpClient. My GetAsyncs are working perfectly fine both when used in Debug and Release mode. The problem occurs when I try to PostAsync a large picture to the API in Release mode. The PostAsync gets cancelled and a WebException is raised (with the message: "A task was cancelled"). I do not cancel the task anywhere in my code. Increasing the timeout doesn't work either - the error occurs approximately 20 seconds after PostAsync gets fired. In Debug mode the PostAsync works fine and uploads a picture in a few seconds when proper connection quality exists. To get it working in Release I need to check the Shared Runtime usage option in configuration. What might be the cause of such behavior? I don't want to use Shared Runtime in my application as I need to release it in Play Store.