When using the Gurobi Cluster Manager, you might receive the error "Unauthorized access". This error indicates that there is a problem with the method of authentication used to connect to the Cluster Manager.
When using a username and password to authenticate with the Cluster Manager, a temporary web token that is valid for eight hours is assigned to the user. After eight hours have elapsed, the Cluster Manager session will end and the solver could suddenly terminate with an Unauthorized access error.
API key authentication
For a more secure and reliable way to authenticate with the Cluster Manager, Gurobi highly recommends using an API key. With this authentication approach, an Unauthorized access error indicates that the API key is invalid.