As read in https://community.home-assistant.io/t/volvo-on-call-api-to-be-discontinued/856123 the Volvo on Call integration will not work anymore with old API. Following https://developer.volvocars.com/apis/docs/getting-started/ there is now an application on developer portal of Volvocars needed.
The integration needs to implement this new OAuth Authentication method and may be it also needs to switch to the current API.
I’ve had an email from Volvo (noreply@email.volvocars.co.uk) with the subject Important: API to be discontinued which reads: The API you are using to communicate with your Volvo vehicle seems to be outdated. It could be that you run it through home automation technology or similar. Unfortunately, this API will be discontinued. At Volvo Cars w...