Starting a few weeks ago, most requests to the REST API (specifically, the VRP API) are failing with the error "498 - Invalid Token".
From what I've gathered, error 498 implies an expired token, but the token used is a token that was generated immediately prior to the request.
The token is obtained by POSTing to https://www.arcgis.com/sharing/rest/oauth2/token/ , with grant_type set to client_credentials, passing client_id, client_secret and f=json. Then, the token is appended on a request to https://logistics.arcgis.com/arcgis/rest/services/World/VehicleRoutingProblem/GPServer/SolveVehicleRoutingProblem/submit… , in the "token" field.
Has there been any changes to the way tokens are supposed to be generated/consumed?