It's difficult / impossible to discern the cause of this message without knowing more information. And it may be best for you to open a case with Tableau Support. I've seen messages like this, and there's a number of variables that can cause this. What release are you on? And do you have sufficient computer resources (i.e. cpu, ram, etc.)
Jeff is on the right track about the issue. It's generally lack of resources to display the dashboard. Open a support case with Tableau and they will dig through the logs to locate that session ID for more clues. They will probably ask for Windows event viewer logs as well. Good luck!