Codemagic APP_STORE_CONNECT_PRIVATE_KEY Provided value is not valid - flutter

Question

I'm trying to sign the iOS build on Codemagic using YAML workflow. Following this document I encrypted and added the following environment variables:
APP_STORE_CONNECT_KEY_IDENTIFIER
APP_STORE_CONNECT_ISSUER_ID
APP_STORE_CONNECT_PRIVATE_KEY
CERTIFICATE_PRIVATE_KEY
On running the workflow I'm getting error Provided value "VALUE of APP_STORE_CONNECT_PRIVATE_KEY" is not valid. What to make this env variable value valid? I also tried adding base64 encoding for this value, but it still shows the same error.
Here's my codemagic.yaml file:
workflows:
ios-workflow:
name: iOS Workflow
# instance_type: mac_mini
max_build_duration: 120
environment:
groups:
- store
vars:
XCODE_WORKSPACE: "Runner.xcworkspace"
XCODE_SCHEME: "Runner"
BUNDLE_ID: "*MY_BUNDLE_ID*"
flutter: stable
xcode: latest
cocoapods: default
scripts:
- name: Set up keychain to be used for codesigning using Codemagic CLI 'keychain' command
script: |
keychain initialize
- name: Fetch signing files
script: |
# Failing command with invalid APP_STORE_CONNECT_PRIVATE_KEY
**app-store-connect fetch-signing-files $BUNDLE_ID --type IOS_APP_STORE --create**
- name: Use system default keychain
script: |
keychain add-certificates
Error:
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/cli_app.py", line 201, in invoke_cli
CliApp._running_app = cls._create_instance(parser, args)
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/cli_app.py", line 130, in _create_instance
instance = cls.from_cli_args(cli_args)
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/tools/app_store_connect.py", line 116, in from_cli_args
private_key_argument = AppStoreConnectArgument.PRIVATE_KEY.from_args(cli_args)
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/argument/argument.py", line 55, in from_args
return self.value.type.from_environment_variable_default()
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/argument/typed_cli_argument.py", line 42, in from_environment_variable_default
return cls(os.environ[cls.environment_variable_key], from_environment=True)
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/argument/typed_cli_argument.py", line 33, in init
self.value: T = self._parse_value()
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/argument/typed_cli_argument.py", line 129, in _parse_value
return super()._parse_value()
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/argument/typed_cli_argument.py", line 57, in _parse_value
return self._apply_type(value)
File "/Users/builder/.pyenv/versions/3.8.7/lib/python3.8/site-packages/codemagic/cli/argument/typed_cli_argument.py", line 52, in _apply_type
raise argparse.ArgumentTypeError(f'Provided value "{value}" is not valid')
argparse.ArgumentTypeError: Provided value "VALUE of APP_STORE_CONNECT_PRIVATE_KEY" is not valid

Answer 1

make sure you downloaded the private API key from App Store Connect in .p8 format and copied the entire contents when paste into environment variable value field.