ECS service did not stabilize
t2.microinstance that you are trying to launch has total memory capacity of 1 GiB.
ECS will try to launch the task into your cluster but it will realize that it cannot meet the requirements because your container instance doesn't have enough available memory (OS processes consume more than 5 MiB of memory) and your task requires "Memory": 995 which is exactly the issue.
Debugging the container itself will not help in this case as there is nothing wrong with it (probably). It is simply the fact that ECS scheduler is unable to meet the specified requirements to launch the task, therefore it cannot do anything else other than failing and giving a "helpful" message.
There are various things that can cause scheduler to fail to launch a task and it should always give a hint about the problem. In you case, it "clearly" states that you don't have enough memory. Other thing to look for are daemon tasks that can be launched only once per container instance (this accidentally happened to me).