I have a problem with running a task from Qalyptus desktop. Connection is working good. The problem seems to occur when the data needs to be exported. I have check the security on the temporary folders but this seems ok.
The error you encounter occurs when Qlik Sense not working correctly (especially: Qlik Sense Proxy service) or when you have Network issues.
Please can you try restarting Qlik Sense Services (If this does not impact other users)?