Container not running error for docker exec command

This is how my Dockerfile looks like

FROM elixir:1.10.4-alpine AS build

ARG CIRCLE_BUILD_NUM
ENV CIRCLE_BUILD_NUM=$CIRCLE_BUILD_NUM

ENV MIX_ENV=prod \
  LANG=C.UTF-8

RUN mix local.hex --force && \
    mix local.rebar --force

# Create the application build directory
RUN mkdir /apps
COPY . /apps
WORKDIR /apps/

COPY mix.exs mix.lock ./
COPY config config
RUN mix deps.get
RUN mix deps.compile

#releases
RUN MIX_ENV=prod mix release my_app

FROM alpine:3.12 as apps
WORKDIR /apps

RUN apk add --no-cache libressl ncurses-libs

RUN mkdir -p /apps/my_app

# create a new user
RUN addgroup -S elixir_app && adduser -S elixir_app -G elixir_app
RUN chown elixir_app:elixir_app /apps
USER elixir_app

COPY --from=build --chown=elixir_app:elixir_app /apps/_build/prod/rel/my_app /apps/my_app

And this is my docker-compose file

version: '3.2'

networks:
  net:

services:
  my_app:
   container_name: my_app
    image: "my_app/myapp-${CIRCLE_BUILD_NUM}"
    environment:
     ----------------------
    expose:
      - "${PORT}"
    ports:
      - "${PORT}:${PORT}"
    command: /apps/my_app/bin/my_app start

When I run docker-compose -f docker-compose.yml up -dI get

Starting my_app_1 … done

But When I run

docker exec -it my_app  /apps/my_app/bin/my_app eval "MyApp.Release.migrate"

getting

Error response from daemon: Container e91f88998632481a657d5c66eafaf4f970a4e3203aac129c46d194f31bcdab63 is not running

Can anyone help me with this?