Lack of compute or memory resources on the machine hosting a simulator/emulator.App instability (maybe the app itself exhibits erratic behavior, even when used by a human!).Unwarranted assumptions made by the test author about app or device speed, app state, screen size, or dynamic content.But without an investigation that proves this to be the case for your particular test, the problem may with equal probability lie in any number of other areas, for example: It may indeed be the case that Appium is responsible for unreliable behavior, and regrettably this does happen in reality. In reality, the situation is much more complex.

The blame here is often put on Appium-if a test passes once when run locally, surely any future failures are due to a problem with the automation technology? It's a tempting position to take, especially because it takes us (the test authors) and our apps out of the crosshairs of blame, and allows us to place responsibility on something external that we don't control (scapegoat much?). According to common usage, 'flakey' is synonymous with 'unreliable'-the test passes some times and fails other times. No discussion of functional test reliability would be complete without addressing the concept of 'flakiness'. In other ways, the accusation is misplaced, because there are strategies we can use to make sure our tests don't run into common pitfalls. In some ways the accusation is true: there are fundamental speed limits to the automation technologies Appium relies on, and in the world of full-fledged functional testing there are a host of environmental problems which can contribute to test instability. Let's face it, Appium tests have sometimes been accused of being slow and unreliable. Making your Appium tests fast and reliable Part 1

Appium server flags