I'm guessing that what was meant by "rebooting the Tableau server" is that the Tableau server application was rebooted, not the actual server that it resides on. Try the 'Restart server' action.
I arranged for the server to be rebooted. Unfortunately I'm still having the same issue.
I have a number of dashboards within one particular workbook which load very quickly in Tableau desktop but do not load in Server. I basically get that spinning wheel non stop.
All of my other workbooks are loading fine in Server and performance is fairly good.
If anyone is able to provide any insights or solutions in would be much appreciated,