CosmosDB Emulaor won't work - Query Explorer keep on running...

If you getting this error or with similar string:

{"readyState":4,"responseText":"{\"code\":\"ServiceUnavailable\",\"message\":\"Service is currently unavailable.\\r\\nActivityId: 9c9f56f8-91f9-4fad-b592-0c6bd5bbd300\"}","responseJSON":{"code":"ServiceUnavailable","message":"Service is currently unavailable.\r\nActivityId: 9c9f56f8-91f9-4fad-b592-0c6bd5bbd300"},
"status":503,
"statusText":"error"}

There are few suggestions to fix this error like perform a "Reset Data" on the Emulator. 
Sometimes this doesn't even work.

Restarting PC have worked for me all the time. 

Please try and let me know if it fixed your issue!