The best way to investigate the root cause of this issue will be to contact Tableau Support. You'll want to provide logs, which can be gathered following these instructions: http://onlinehelp.tableau.com/current/server/en-us/help.htm#qs_logdownload.html
Once you've gathered the log files, your current version number of Tableau Server, and any screenshots applicable to the issue, you can file support case here: Submit a case to our support team | Tableau Software
Let me know if you have any additional questions regarding this!
1 of 1 people found this helpful
We ended up finding the issue in a Dashboard a user was attempting to view. One of the quick filters used a calculated field that had a contains function. The dataset had over 10 millions records and caused the entire server to seize up while it filtered. They happened to have done it when the notifications job started.