In my case, it's because I accidentally added a giant file to my uncommitted push
FROM python:2.7
LABEL maintainer="Kotulskyi Volodymyr"
WORKDIR /var/opt
COPY ./app ./
RUN pip install -r requirements.txt
CMD python app.pydocker run \
-d -ti \
-p 5000:80 \
--name course-app \