You first need to create an extract of the data
Then you upload to Server (number 3 in the below) (you may need steps 1&2 also...)
** IMPORTANT: under authentication choose - embed password **
Once that's done, on Tableau Server, under Tasks you can choose a schedule, tick, choose Run Now and see what happens... if you get an error, it will be displayed top right, next to a warning flag.
Hope that helps!
Often when this scenario arises, it is because the Server host does not have the same TNSnames.ora entries as your personal machine with Desktop on it, so the Server ends up taking a TNSnames error.
(Your Server Administrator can check if this is the case.)
In the "old" days (prior to 9.0) one hack that worked was to copy paste the actual TNS entry (with all the parentheses in it) directly into the Connection Dialog box, but I have not yet tried that in 9.0 In 6.x, 7.x, and 8.x we found that that allowed the Server to connect to various Oracle sources even when the Server's host itself did not have the corresponding entries in its TNSnames.ora.
It is difficult for a Tableau Server Admin to have to add more TNS entries every time a new Workbook gets published that contains a new one, but that would be the more "correct" way to configure the system.
Thanks Ken, you're a few steps ahead of me...
I was going to get onto that if the OP was using an extract, and it wasn't a problem with embedded credentials.
It could also be related to the permissions of the Server account (Run As User), my TNS name file was an easy check, it was the user account which caused me ALOT of issues!
Andhika... hope something there helps, do post back if you have any queries...