Internal Server Error Accessing the Hub on a MultiNode System. Error in Repository Log File.

If you receive an Internal Service Error when attempting to access the Hub on all engines but the QMC functions normally check the Repository System log.
This file will be located in %ProgramData%\Qlik\Sense\Logs\Repository\Trace

If you see error messages similar to this in the Repository_System.txt file:
346    20160830T132604.920-0400    ERROR    QLIKSERVER1    System.Repository.Qlik.Sense.Common.Communication.REST.Server.RESTEngine    31    70025179-46a3-4532-9302-14e3cfa18b5b    DOMAIN\QLIKSERVICE    Sequence contains more than one element                70025179-46a3-4532-9302-14e3cfa18b5b

You have been impacted by an issue that results in duplicate values in the table, please raise a case so that we can assist you with this further.

The HubService uses Rest API calls to determine which engines are available for the hub and applications, some of this information is determined by which Engines are up and available. The API does not gracefully handle duplicate statuses for these services which causes errors in the central repository and the hub service. Hence the internal server error.

The duplicate values in the ServiceStatus table needs to be cleared in the databases present on each node and the snapshot reset. This operation is not supported without assistance from support.