In SharePoint server 2013, to refresh the data manually in PivotTables need to go for Data -> Refresh All Connections as shown in the image below.
While refreshing data I got an error like “An error occurred during an attempt to establish connection to external data source…”
After checking the error in Logs I have find that the issue with identity currently set. When we access to refresh the data in PivotTables Claims to windows token service (C2WTS) will be used. If C2WTS is running with domain account that domain account needs permissions on the SharePoint server where it is running.
C2WTS domain account must be in SharePoint server’s local administration group where it is running and it has to impersonate the client after the authentication, Works to log an as service and it needs to be act as part of the operating system.
To access the local security policy of the server, Go to Administrative Tools -> Local Security Policy -> Local Policies -> User Rights Assignments
By adding the permissions to the account that running Claims to windows token service, we need to restart the service on each server it is running.