This error can have several possible causes.
The Access Connect Service on the server is not logged into an account with the relevant permissions (We always advise to use the Domain Administrator account).
Your Database has not been synchronised with Workspace. You will need to log into Dimensions as the relevant user. (If you have multiple databases, you will need to sync all databases for the unauthorised error to disappear)
The email address for the Workspace administrator account(s) may have changed but Workspace has not been informed in which case that person will no longer be considered an Administrator.
To fix point 1, please speak with your IT department to get the Access connect Service running with a server profile with full domain admin permissions.
To fix point 2, you will need to go into Dimensions and sync all the accounts with Workspace using the following steps:
Select System, Data Utilities
Select Synchronise aCloud apps.
To fix point 3, please raise a new case with Access to request that all relevant email addresses in Workspace are updated to be correct.