How to fix denied: requested access to the resource is denied in Docker

The most common cause is an incorrectly tagged image. Docker Hub requires images to follow the format username/image:tag.

# Check your current image tags
docker images

# If your image is tagged as 'myapp:latest' without a username, retag it:
docker tag myapp:latest YOUR_DOCKERHUB_USERNAME/myapp:latest

# Verify the new tag
docker images | grep myapp

Replace YOUR_DOCKERHUB_USERNAME with your actual Docker Hub username. Find your username at [hub.docker.com](https://hub.docker.com) after logging in.

Ensure you are authenticated with Docker Hub:

# Log in interactively
docker login

# For CI/CD, use stdin to avoid exposing credentials
echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin

After successful login, you should see "Login Succeeded". Credentials are stored in ~/.docker/config.json.

If login appears successful but push still fails, your cached credentials may be corrupted:

# Log out from Docker Hub
docker logout

# Remove cached credentials
rm ~/.docker/config.json

# Log in again
docker login

On Windows, the config file is at C:\Users\<username>\.docker\config.json. On macOS, credentials may also be stored in Keychain.

Docker Hub requires email verification before you can push images:

1. Go to [hub.docker.com](https://hub.docker.com) and log in
2. Click on your profile icon and select "Account Settings"
3. Check if your email is verified
4. If not, click "Resend verification email"
5. Click the link in the verification email
6. Retry your docker push command

If pushing to an organization repository, verify you have push access:

1. Go to the repository page on Docker Hub
2. Click "Settings" then "Permissions"
3. Verify your account has "Write" or "Admin" access
4. If not, ask the organization owner to grant access

For your own repositories, ensure the repository name matches your username exactly (case-sensitive).

After fixing the authentication and tagging, push your image:

# Push to Docker Hub
docker push YOUR_DOCKERHUB_USERNAME/myapp:latest

# For organizations
docker push YOUR_ORG_NAME/myapp:latest

You should see layer upload progress. If it fails immediately, check the error message for clues.