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Receiving OSError: [Errno 8] Exec format error in app running in Docker Container

I have a React/Flask app running within a Docker container. There is no issue with me building the project using docker-compose, and running the app itself in the container. Where I am running into issues is a particular API route that is supposed to fetch user profiles from the DB, encrypt the values in a text file, and return to the frontend for download. The encryption script is written in C, though the API route is written in Python. When I try and encrypt through the app running in Docker, I am given the following error message:
OSError: [Errno 8] Exec format error: './app/Crypto/encrypt.exe'
I know the following command works in the CLI if invoked outside of the Docker Container (still invoked at the same directory level as it would in app):
./app/Crypto/encrypt.exe -k ./app/Crypto/secretkey -i ./profile.txt -o ./profile.encr
I am using the following Python code to invoke the command in the API route which is where it fails:
proc = subprocess.Popen(f"./app/Crypto/encrypt.exe -k ./app/Crypto/secretkey -i ./{profile.profile_name}.txt -o ./{profile.profile_name}.encr", shell=True)
The Dockerfile for my backend is pasted below:
FROM python:3
WORKDIR /app
ENV FLASK_APP=main.py
COPY ./requirements.txt .
RUN pip install -r requirements.txt
COPY . .
CMD ["python", "main.py"]
I have tried to tackle the issue a few different ways:
By default my Docker Container was built with Architecture of ARM64. I read that the OS Error was caused by Architecture not being AMD64, so I rebuilt the container with AMD64 and it gave me the same error.
In case this was a permissions error, I ran chmod +rwx on encrypt.exe through the Dockerfile when building the container. Pretty sure it has nothing to do with permissions especially as it still failed.
I added a shebang (#!/bin/bash) to the script as well as to the Dockerfile.
At the end of the day I know I am failing when using subprocess.Popen, so I am positive I must be missing something when invoking the script using Python, or there is a configuration in my Docker Container that is preventing this functionality. My machine is a Macbook Pro which the script runs fine on. The script has also successfully been utilized on a machine running Linux.
Any chances folks have seen similar issues arise with this error? Thanks in advance!

So thanks to David Maze's comment on this, I followed the lead that maybe the executable I wanted to run needed to be built within the Dockerfile. I destroyed my original container, added in a step to run the Makefile that generates the executable, and finally ran the program through the app running in the Docker container. This did the trick! Not sure as to why the executable needed to be compiled within the Docker container, but running 'make' on the Makefile within the Dockerfile did the trick.

Why can't I run "python manage.py startup APP_NAME" with django?

I'm trying to build a Django app, but it doesn't let me startup the app so I can bring it to the development server. I run python manage.py startup APP_NAME, where I expect the app to run. Instead, I get an error saying there is no such file or directory called manage.py. However, I have it open.
Is there a reason for this?

Perhaps what you need to ensure on your terminal what is the directory your project is located, by using command prompt "ls" if you are using Linux, or dir on Windows, then you need to activate your virtual environment using source virtual_env_name/bin/activate... then you can execute python manage.py

You need to run:
python manage.py startapp APP_NAME
to create new app in django

Django, how to run a command through Windows Task Scheduler

How to schedule and run a specific command in django using Windows Task Scheduler. My django project is not currently local server deployed but using the manual set up just like activating the virtual environment and then typing the python manage.py runserver on terminal rather deploying through xampp or laragon. But i am bit confused on how to achieve to schedule and run a command like python manage py get_source through the use of Windows Task Scheduler.

Don't know if you're still looking for this but I found a working solution here - configure .bat file to run commands in Django Virtual Env
Very simple; point to the location of your project directory...
cd C:\webapps\my-project-dir-with-manage.py-inside
copy and paste the contents of the system generated activate.bat,found inside your venv/Scripts folder...
add your command line...
.\manage.py <your command here>
save as myfile.bat, and schedule via the Windows Task Scheduler.
Super simple.

I had the same problem.
The main issue is, that you missed the full path to python.exe as an execution application. "Python" will not work.
And then your application as an argument.
Additionally, to that, you can add w to py. This will make it runnable on windows without a .bat file.
Application to execute:
C:\user\python.exe Argument: manage.pyw runserver

Django shell mode in docker

I am learning how to develop Django application in docker with this official tutorial: https://docs.docker.com/compose/django/
I have successfully run through the tutorial, and
docker-compose run web django-admin.py startproject composeexample . creates the image
docker-compose up runs the application
The question is:
I often use python manage.py shell to run Django in shell mode, but I do not know how to achieve that with docker.

I use this command (when run with compose)
docker-compose run <service_name> python manage.py shell
where <service name> is the name of the docker service(in docker-compose.yml).
So, In your case the command will be
docker-compose run web python manage.py shell
https://docs.docker.com/compose/reference/run/
When run with Dockerfile
docker exec -it <container_id> python manage.py shell

Run docker exec -it --user desired_user your_container bash Running this command has similar effect then runing ssh to remote server - after you run this command you will be inside container's bash terminal. You will be able to run all Django's manage.py commands.
Inside your container just run python manage.py shell

You can use docker exec in the container to run commands like below.
docker exec -it container_id python manage.py shell

If you're using docker-compose you shouldn't always run additional containers when it's not needed to, as each run will start new container and you'll lose a lot of disk space. So you can end up with running multiple containers when you totally won't have to. Basically it's better to:
Start your services once with docker-compose up -d
Execute (instead of running) your commands:
docker-compose exec web ./manage.py shell
or, if you don't want to start all services (because, for example - you want to run only one command in Django), then you should pass --rm flag to docker-compose run command, so the container will be removed just after passed command will be finished.
docker-compose run --rm web ./manage.py shell
In this case when you'll escape shell, the container created with run command will be destroyed, so you'll save much space on your disk.

If you're using Docker Compose (using command docker compose up) to spin up your applications, after you run that command then you can run the interactive shell in the container by using the following command:
docker compose exec <container id or name of your Django app> python3 <path to your manage.py file, for example, src/manage.py> shell
Keep in mind the above is using Python version 3+ with python3.

Local Django server cannot connect when run through Bash on Windows

I recently realized that I could use Bash for Windows as the terminal for use in Pycharm so that the IDE had a proper terminal in it even through it was in Windows. I want to work on a Django project but I realized something strange. When I run the server through the IDE's run button, everything runs as expected. However, when I try to run the server through the command line via
python3 manage.py runserver,
the terminal output is the same, but my browsers cannot connect. Instead they say that the connection was reset. I have full installations of Django and Python for both Windows and the Bash environment and both seem to be fully functional. I can make migrations and create new apps through the command line just fine, but I was wondering if anybody else knew why the Django Server does not connect when run through Bash on Windows