How to Solve:
Please find the below steps to resolve the above error :

Screenshot 1: Turn off firewall on client and server machine
Follow Windows Start >> Search >> Services >> Enter

Screenshot 2:
Screenshot 3:
Screenshot 4: It’s Done, close the windows
Screenshot 5: Go to Server machine >> Windows Start >> Search >> Services >> Enter

Screenshot 6:  Start or Restart the SQL services

If Still your client machine is not working then try below solution:
Please check the network connectivity between client and server
Screenshot 7: Go to Server machine >> Windows start button >> Search >> CMD >> Type ipconfig >> Press enter
Screenshot 8: 
Right click on eZee Version 7 icon and go for open file location

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Screenshot 11: Disable your antivirus