Error while deploying Rasa x: TypeError: unsupported operand type(s) for +: 'NoneType' and 'list'

I’m getting this erros while trying to run Rasa X using docker-compose on AWS

rasa-x_1           | Exception occurred while handling uri: 'http://*****/api/projects/default/git_repositories/1/branches/master?force=true'
rasa-x_1           | Traceback (most recent call last):
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/sanic/app.py", line 976, in handle_request
rasa-x_1           |     response = await response
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/api/decorators.py", line 212, in decorated_function
rasa-x_1           |     return await await_and_return_response(args, kwargs, request)
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/api/decorators.py", line 142, in await_and_return_response
rasa-x_1           |     response = await response
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/api/blueprints/git.py", line 183, in checkout_branch
rasa-x_1           |     await git_service.synchronize_project(force_data_injection=True)
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/services/integrated_version_control/git_service.py", line 756, in synchronize_project
rasa-x_1           |     return await self._force_inject_latest_remote_changes()
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/services/integrated_version_control/git_service.py", line 810, in _force_inject_latest_remote_changes
rasa-x_1           |     await self._inject_data()
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/services/integrated_version_control/git_service.py", line 788, in _inject_data
rasa-x_1           |     SYSTEM_USER,
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/initialise.py", line 300, in inject_files_from_disk
rasa-x_1           |     username,
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/initialise.py", line 144, in inject_domain
rasa-x_1           |     should_dump_domain=False,
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasax/community/services/domain_service.py", line 138, in validate_and_store_domain_yaml
rasa-x_1           |     domain = RasaDomain.from_yaml(domain_yaml)
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasa/core/domain.py", line 133, in from_yaml
rasa-x_1           |     return cls.from_dict(data)
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasa/core/domain.py", line 162, in from_dict
rasa-x_1           |     **additional_arguments,
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasa/core/domain.py", line 417, in __init__
rasa-x_1           |     self.user_actions = action.combine_with_templates(action_names, templates)
rasa-x_1           |   File "/usr/local/lib/python3.7/site-packages/rasa/core/actions/action.py", line 100, in combine_with_templates
rasa-x_1           |     return actions + unique_template_names
rasa-x_1           | TypeError: unsupported operand type(s) for +: 'NoneType' and 'list'

has anybody experienced the same issue?

my domain.yml

--- 
entities: 
  - "positive:positive"
intents: 
  - some-intents
session_config: 
  carry_over_slots_to_new_session: true
  session_expiration_time: 2400