I have published a release “Release 0.5.14 - Bugfix refresh_token error”. This should fix the error:
File “/usr/src/homeassistant/homeassistant/config_entries.py”, line 304, in async_setup
result = await component.async_setup_entry(hass, self) # type: ignore
File “/config/custom_components/mbapi2020/init.py”, line 105, in async_setup_entry
token_info = await mercedes.client.oauth.async_get_cached_token()
File “/config/custom_components/mbapi2020/oauth.py”, line 136, in async_get_cached_token
token_info = await self.async_refresh_access_token(token_info[“refresh_token”])
KeyError: ‘refresh_token’
A ReAuthentication is required - See the red box on the integration page after restart.
Background:
MB changed something in the OAuth Backend. In the past the refresh_token was always present. Now the refresh_token is missing sometimes… 
@bobofruit , @dolam : May I ask you to recheck?
BR
Rene